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Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,*preroll music*\N[filler, please remove in amara]
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Herald: Our next speaker for today is a\Ncomputer science PhD student at UC Santa
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Barbara. He is a member of the Shellfish\NHacking Team and he's also the organizer
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,of the IECTF Hacking Competition. Please\Ngive a big round of applause to Nilo
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Redini.\N[filler, please remove in amara]
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,*applause*\N[filler, please remove in amara]
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Nilo: Thanks for the introduction, hello\Nto everyone. My name is Nilo, and today
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,I'm going to present you my work Koronte:\Nidentifying multi-binary vulnerabilities
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,in embedded firmware at scale. This work\Nis a co-joint effort between me and
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,several of my colleagues at University of\NSanta Barbara and ASU. This talk is going
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,to be about IoT devices. So before\Nstarting, let's see an overview about IoT
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,devices. IoT devices are everywhere. As\Nthe research suggests, they will reach the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,20 billion units by the end of the next\Nyear. And a recent study conducted this
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,year in 2019 on 16 million households\Nshowed that more than 70 percent of homes
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,in North America already have an IoT\Nnetwork connected device. IoT devices make
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,everyday life smarter. You can literally\Nsay "Alexa, I'm cold" and Alexa will
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,interact with the thermostat and increase\Nthe temperature of your room. Usually the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,way we interact with the IoT devices is\Nthrough our smartphone. We send a request
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,to the local network, to some device,\Nrouter or door lock, or we might send the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,same request through a cloud endpoint,\Nwhich is usually managed by the vendor of
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the IoT device. Another way is through the\NIoT hubs, smartphone will send the request
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,to some IoT hub, which in turn will send\Nthe request to some other IoT devices. As
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,you can imagine, IoT devices use and\Ncollect our data and some data is more
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,sensitive than other. For instance, think\Nof all the data that is collected by my
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,lightbulb or data that is collected by our\Nsecurity camera. As such, IoT devices can
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,compromise people's safety and privacy.\NThings, for example, about the security
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,implication of a faulty smartlock or the\Nbrakes of your smart car. So the question
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,that we asked is: Are IoT devices secure?\NWell, like everything else, they are not.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,OK, in 2016 the Mirai botnet compromised\Nand leveraged millions of IoT devices to
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,disrupt core Internet services such as\NTwitter, GitHub and Netflix. And in 2018,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,154 vulnerabilities affecting IoT devices\Nwere published, which represented an
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,increment of 15% compared to 2017 and an\Nincrease of 115% compared to 2016. So then
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,we wonder: So why is it hard to secure IoT\Ndevices? To answer this question we have
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,to look up how IoT devices work and they\Nare made. Usually when you remove all the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,plastic and peripherals IoT devices look\Nlike this. A board with some chips laying
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,on it. Usually you can find the big chip,\Nthe microcontroller which runs the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,firmware and one or more peripheral\Ncontrollers which interact with external
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,peripherals such as the motor of, your\Nsmart lock or cameras. Though the design
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,is generic, implementations are very\Ndiverse. For instance, firmware may run on
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,several different architectures such as\NARM, MIPS, x86, PowerPC and so forth. And
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,sometimes they are even proprietary, which\Nmeans that if a security analyst wants to
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,understand what's going on in the\Nfirmware, he'll have a hard time if he
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,doesn't have the vendor specifics. Also,\Nthey're operating in environments with
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,limited resources, which means that they\Nrun small and optimized code. For
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,instance, vendors might implement their\Nown version of some known algorithm in an
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,optimized way. Also, IoT devices manage\Nexternal peripherals that often use custom
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,code. Again, with peripherals we mean like\Ncameras, sensors and so forth. The
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,firmware of IoT devices can be either\NLinux based or a blob firmware, Linux
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,based are by far the most common. A study\Nshowed that 86% of firmware are based on
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Linux and on the other hand, blobs\Nfirmware are usually operating systems and
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,user applications packaged in a single\Nbinary. In any case, firmware samples are
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,usually made of multiple components. For\Ninstance, let's say that you have your
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,smart phone and you send a request to your\NIoT device. This request will be received
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,by a binary which we term as body binary,\Nwhich in this example is an webserver. The
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,request will be received, parsed, and then\Nit might be sent to another binary code,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the handler binary, which will take the\Nrequest, work on it, produce an answer,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,send it back to the webserver, which in\Nturn would produce a response to send to
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the smartphone. So to come back to the\Nquestion why is it hard to secure IoT
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,devices? Well, the answer is because IoT\Ndevices are in practice very diverse. Of
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,course, there have been various work that\Nhave been proposed to analyze and secure
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,firmware for IoT devices. Some of them\Nusing static analysis. Others using
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,dynamic analysis and several others using\Na combination of both. Here I wrote
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,several of them. Again at the end of the\Npresentation there is a bibliography with
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the title of these works. Of course, all\Nthese approaches have some problems. For
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,instance, the current dynamic analysis are\Nhard to apply to scale because of the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,customized environments that IoT devices\Nwork on. Usually when you try to
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,dynamically execute a firmware, it's gonna\Ncheck if the peripherals are connected and
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,are working properly. In a case where you\Ncan't have the peripherals, it's gonna be
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,hard to actually run the firmware. Also\Ncurrent static analysis approaches are
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,based on what we call the single binary\Napproach, which means that binaries from a
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,firmware are taken individually and\Nanalysed. This approach might produce many
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,false positives. For instance, so let's\Nsay again that we have our two binaries.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,This is actually an example that we found\Non one firmware, so the web server will
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,take the user request, will parse the\Nrequest and produce some data, will set
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,this data to an environment variable and\Neventually will execute the handle binary.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Now, if you see the parsing function\Ncontains a string compare which checks if
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,some keyword is present in the request.\NAnd if so, it just returns the whole
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,request. Otherwise, it will constrain the\Nsize of the request to 128 bytes and
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,return it. The handler binary in turn when\Nspawned will receive the data by doing a
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,getenv on the query string, but also will\Ngetenv on another environment variable
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,which in this case is not user controlled\Nand they user cannot influence the content
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,of this variable. Then it's gonna call\Nfunction process_request. This function
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,eventually will do two string copies. One\Nfrom the user data, the other one from the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,log path on two different local variables\Nthat are 128 bytes long. Now in the first
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,case, as we have seen before, the data can\Nbe greater than 128 bytes and this string
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,copy may result in a bug. While in the\Nsecond case it will not. Because here we
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,assume that the system handles its own\Ndata in a good manner. So throughout this
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,work, we're gonna call the first type of\Nbinary, the setter binary, which means
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,that it is the binary that takes the data\Nand set the data for another binary to be
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,consumed. And the second type of binary we\Ncalled them the getter binary. So the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,current bug finding tools are inadequate\Nbecause other bugs are left undiscovered
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,if the analysis only consider those\Nbinaries that received network requests or
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,they're likely to produce many false\Npositives if the analysis considers all of
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,them individually. So then we wonder how\Nthese different components actually
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,communicate. They communicate through what\Nare called interprocess communication,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,which basically it's a finite set of\Nparadigms used by binaries to communicate
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,such as files, environment variables, MMIO\Nand so forth. All these pieces are
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,represented by data keys, which are file\Nnames, or in the case of the example
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,before here on the right, it's the query\Nstring environment variable. Each binary
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,that relies on some shared data must know\Nthe endpoint where such data will be
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,available, for instance, again, like a\Nfile name or like even a socket endpoint
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,or the environment variable. This means\Nthat usually, data keys are coded in the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,program itself, as we saw before. To find\Nbugs in firmware, in a precise manner, we
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,need to track how user data is introduced\Nand propagated across the different
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,binaries. Okay, let's talk about our work.\NBefore you start talking about Karonte, we
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,define our threat model. We hypotesized\Nthat attacker sends arbitrary requests
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,over the network, both LAN and WAN\Ndirectly to the IoT device. Though we said
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,before that sometimes IoT device can\Ncommunicate through the clouds, research
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,showed that some form of local\Ncommunication is usually available, for
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,instance, during the setup phase of the\Ndevice. Karonte is defined as a static
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,analysis tool that tracks data flow across\Nmultiple binaries, to find
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,vulnerabilities. Let's see how it works.\NSo the first step, Karonte find those
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,binaries that introduce the user input\Ninto the firmware. We call these border
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,binaries, which are the binaries, that\Nbasically interface the device to the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,outside world. Which in the example is our\Nweb server. Then it tracks how a data is
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,shared with other binaries within the\Nfirmware sample. Which we'll understand in
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,this example, the web server communicates\Nwith the handle binary, and builds what we
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,call the BDG. BDG which stands for binary\Ndependency graph. It's basically a graph
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,representation of the data dependencies\Namong different binaries. Then we detect
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,vulnerabilities that arise from the misuse\Nof the data using the BDG. This is an
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,overview of our system. We start by taking\Na packed firmware, we unpack it. We find
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the border binaries. Then we build the\Nbinary dependency graph, which relies on a
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,set of CPFs, as we will see soon. CPF\Nstands for Communication Paradigm Finder.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Then we find the specifics of the\Ncommunication, for instance, like the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,constraints applied to the data that is\Nshared through our module multi-binary
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,data-flow analysis. Eventually we run our\Ninsecure interaction detection module,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,which basically takes all the information\Nand produces alerts. Our system is
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,completely static and relies on our static\Ntaint engine. So let's see each one of
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,these steps, more in details. The\Nunpacking procedure is pretty easy, we use
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the off-the-shelf firmware unpacking tool\Nbinwalk. And then we have to find the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,border binaries. Now we see that border\Nbinaries basically are binaries that
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,receive data from the network. And we\Nhypotesize that will contain parsers to
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,validate the data that they received. So\Nin order to find them, we have to find
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,parsers which accept data from network and\Nparse this data. To find parsers we rely
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,on related work, which basically uses a\Nfew metrics and define through a number
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the likelihood for a function to contain\Nparsing capabilities. These metrics that
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,we used are number of basic blocks, number\Nof memory comparison operations and number
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,of branches. Now while these define\Nparsers, we also have to find if a binary
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,takes data from the network. As such, we\Ndefine two more metrics. The first one, we
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,check if binary contains any network\Nrelated keywords as SOAP, http and so
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,forth. And then we check if there exists a\Ndata flow between read from socket and a
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,memory comparison operation. Once for each\Nfunction, we got all these metrics, we
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,compute what is called a parsing score,\Nwhich basically is just a sum of products.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Once we got a parsing score for each\Nfunction in a binary, we represent the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,binary with its highest parsing score.\NOnce we got that for each binary in the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,firmware we cluster them using the DBSCAN\Ndensity based algorithm and consider the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,cluster with the highest parsing score as\Ncontaining the set of border binaries.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,After this, we build the binary dependency\Ngraph. Again the binary dependency graph
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,represents the data dependency among the\Nbinaries in a firmware sample. For
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,instance, this simple graph will tell us\Nthat a binary A communicates with binary C
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,using files and the same binary A\Ncommunicates with another binary B using
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,environment variables. Let's see how this\Nworks. So we start from the identified
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,border binaries and then we taint the data\Ncompared against network related keywords
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,that we found and run a static analysis,\Nstatic taint analysis to detect whether
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the binary relies on any IPC paradigm to\Nshare the data. If we find that it does,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,we establish if the binary is a setter or\Na getter, which again means that if the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,binary is setting the data to be consumed\Nby another binary, or if the binary
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,actually gets the data and consumes it.\NThen we retrieve the employed data key
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,which in the example before was the\Nkeyword QUERY_STRING. And finally we scan
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the firmware sample to find other binaries\Nthat may rely on the same data keys and
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,schedule them for further analysis. To\Nunderstand whether a binary relies on any
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,IPC, we use what we call CPFs, which again\Nmeans communication paradigm finder. We
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,design a CPF for each IPC. And the CPFs\Nare also used to find the same data keys
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,within the firmware sample. We also\Nprovide Karonte with a generic CPF to
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,cover those cases where the IPC is\Nunknown. Or those cases were the vendor
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,implemented their own versions of some\NIPC. So for example they don't use the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,setenv. But they implemented their own\Nsetenv. The idea behind this generic CPF
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,that we call the semantic CPF is that data\Nkeys has to be used as index to set, or to
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,get some data in this simple example. So\Nlet's see how the BDG algorithm works. We
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,start from the body binary, which again\Nwill start from the server request and
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,will pass the URI and we see that here. it\Nruns a string comparison against some
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,network related keyword. As such, we taint\Nthe variable P. And we see that the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,variable P is returned from the function\Nto these two different points. As such, we
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,continue. And now we see that data gets\Ntainted and the variable data, it's passed
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,to the function setenv. At this point, the\Nenvironment CPF will understand that
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,tainted data is passed, is set to an\Nenvironment variable and will understand
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,that this binary is indeed the setter\Nbinary that uses the environment. Then we
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,retrieve the data key QUERY_STRING and\Nwe'll search within the firmware sample
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,all the other binaries that rely on the\Nsame data key. And it will find that this
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,binary relies on the same data key and\Nwill schedule this for further analysis.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,After this algorithm we build the BDG by\Ncreating edges between setters and getters
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,for each data key. The multi binary data\Nflow analysis uses the BDG to find and
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,propagate the data constraints from a\Nsetter to a getter. Now, through this we
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,apply only the least three constraints,\Nwhich means that ideally between two
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,program points, there might be an infinite\Nnumber of parts and ideally in theory an
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,infinite amount of constraints that we can\Npropagate to the setter binary to the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,getter binary. But since our goal here is\Nto find bugs, we only propagate the least
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,strict set of constraints. Let's see an\Nexample. So again, we have our two
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,binaries and we see that the variable that\Nis passed to the setenv function is data,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,which comes from two different parts from\Nthe parse URI function. In the first case,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the data that its passed is unconstrained\None in the second case, a line 8 is
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,constrained to be at most 128 bytes. As\Nsuch, we only propagate the constraints of
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the first guy. In turn, the getter binary\Nwill retrieve this variable from the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,environment and set the variable query.\NOh, sorry. Which in this case will be
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,unconstrained. Insecure interaction\Ndetection run a static taint analysis and
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,check whether tainted data can reach a\Nsink in an unsafe way. We consider as
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,sinks memcpy like functions which are\Nfunctions that implement semantically
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,equivalent memcyp, strcpy and so forth. We\Nraise alert if we see that there is a
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,dereference of a tainted variable and if\Nwe see there are comparisons of tainted
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,variables in loop conditions to detect\Npossible DoS vulnerabilities. Let's see an
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,example again. So we got here. We know\Nthat our query variable is tainted and
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,it's unconstrained. And then we follow the\Ntaint in the function process_request,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,which we see will eventually copy the data\Nfrom q to arg. Now we see that arg is 128
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,bytes long while q is unconstrained and\Ntherefore we generate an alert here. Our
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,static taint engine is based on BootStomp\Nand is completely based on symbolic
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,execution, which means that the taint is\Npropagated following the program data
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,flow. Let's see an example. So assuming\Nthat we have this code, the first
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,instruction takes the result from some\Nseed function that might return for
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,instance, some user input. And in a\Nsymbolic world, what we do is we create a
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,symbolic variable ty and assign to it a\Ntainted variable that we call TAINT_ty,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,which is the taint target. The next\Ndestruction X takes the value ty plus 5
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and a symbolic word. We just follow the\Ndata flow and x gets assigned TAINT_ty
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,plus 5 which effectively taints also X. If\Nat some point X is overwritten with some
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,constant data, the taint is automatically\Nremoved. In its original design,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,BootStomp, the taint is removed also when\Ndata is constrained. For instance, here we
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,can see that the variable n is tainted but\Nthen is constrained between two values 0
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and 255. And therefore, the taint is\Nremoved. In our taint engine we have two
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,additions. We added a path prioritization\Nstrategy and we add taint dependencies.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,The path prioritization strategy valorizes\Npaths that propagate the taint and
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,deprioritizes those that remove it. For\Ninstance, say again that some user input
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,comes from some function and the variable\Nuser input gets tainted. Gets tainted and
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,then is passed to another function called\Nparse. Here, if you see there are possibly
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,an infinite number of symbolic parts in\Nthis while. But only 1 will return tainted
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,data. While the others won't. So the path\Nprioritization strategy valorizes this
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,path instead of the others. This has been\Nimplemented by finding basic blocks within
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,a function that return a nonconstant data.\NAnd if one is found, we follow its return
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,before considering the others. Taint\Ndependencies allows smart untaint
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,strategies. Let's see again the example.\NSo we know that user input here is
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,tainted, is then parsed and then we see\Nthat it's length is checked and stored in
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,a variable n. Its size is checked and if\Nit's higher than 512 bytes, the function
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,will return. Otherwise it copies the data.\NNow in this case, it might happen that if
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,this strlen function is not analyzed\Nbecause of some static analysis input
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,decisions, the taint tag of cmd might be\Ndifferent from the taint tag of n and in
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,this case, though, and gets untainted, cmd\Nis not untainted and the strcpy can raise,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,sorry, carries a false positive. So to fix\Nthis problem. Basically we create a
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,dependency between the taint tag of n and\Nthe taint tag of cmd. And when n gets
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,untainted, cmd gets untainted as well. So\Nwe don't have more false positives. This
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,procedure is automatic and we find\Nfunctions that implement streamlined
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,semantically equivalent code and create\Ntaint tag dependencies. OK. Let's see our
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,evaluation. We ran 3 different evaluations\Non 2 different data sets. The first one
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,composed by 53 latest firmware samples\Nfrom seven vendors and a second one 899
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,firmware gathered from related work. In\Nthe first case, we can see that the total
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,number of binaries considered are 8.5k,\Nfew more than that. And our system
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,generated 87 alerts of which 51 were found\Nto be true positive and 34 of them were
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,multibinary vulnerabilities, which means\Nthat the vulnerability was found by
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,tracking the data flow from the setter to\Nthe getter binary. We also ran a
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,comparative evaluation, which basically we\Ntried to measure the effort that an
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,analyst would go through in analyzing\Nfirmware using different strategies. In
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the first one, we consider each and every\Nbinary in the firmware sample
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,independently and run the analysis for up\Nto seven days for each firmware. The
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,system generated almost 21000 alerts.\NConsidering only almost 2.5k binaries. In
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the second case we found the border\Nbinaries, the parsers and we statically
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,analyzed only them, and the system\Ngenerated 9.3k alerts. Notice that in this
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,case, since we don't know how the user\Ninput is introduced, like in this
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,experiment, we consider every IPC that we\Nfind in the binary as a possible source of
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,user input. And this is true for all of\Nthem. In the third case we ran the BDG but
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,we consider each binaries independently.\NWhich means that we don't propagate
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,constraints and we run a static single\Ncorner analysis on each one of them. And
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the system generated almost 15000 alerts.\NFinally, we run Karonte and the generated
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,alerts were only 74. We also run a larger\Nscale analysis on 899 firmware samples.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,And we found that almost 40% of them were\Nmulti binary, which means that the network
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,functionalities were carried on by more\Nthan one binary. And the system generated
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,1000 alerts. Now, there is a lot going on\Nin this table, like details are on the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,paper. Here in this presentation I just go\Nthrough some as I'll motivate. So we found
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,that on average, a firmware contains 4\Nborder binaries. A BDG contains 5 binaries
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and some BDG have more than 10 binaries.\NAlso, we plot some statistics and we found
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,that 80% of the firmware were analysed\Nwithin a day, as you can see from the top
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,left figure. However, experiments\Npresented a great variance which we found
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,was due to implementation details. For\Ninstance we found that angr would take
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,more than seven hours to build some CFGs.\NAnd sometimes they were due to a high
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,number of data keys. Also, we found that\Nthe number of paths, as you can see from
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,this second picture from the top, the\Nnumber of paths do not have an impact on
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the total time. And as you can see from\Nthe bottom two pictures, performance not
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,heavily affected by firmware size.\NFirmware size here we mean the number of
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,binaries in a firmware sample and the\Ntotal number of basic blocks. So let's see
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,how to run Karonte. The procedure is\Npretty straightforward. So first you get a
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,firmware sample. You create a\Nconfiguration file containing information
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,of the firmware sample and then you run\Nit. So let's see how. So this is an
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,example of a configuration file. It\Ncontains the information, but most of them
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,are optional. The only ones that are not\Nare this one: Firmware path, that is the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,path to your firmware. And this too, the\Narchitecture of the firmware and the base
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,address if the firmware is a blob, is a\Nfirmware blob. All the other fields are
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,optional. And you can set them if you have\Nsome information about the firmware. A
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,detailed explanation of all of these\Nfields are on our GitHub repo. Once you
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,set the configuration file, you can run\NKaronte. Now we provide a Docker
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,container, you can find the link on our\NGitHub repo. And I'm gonna run it, but
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,it's not gonna finish because it's gonna\Ntake several hours. But all you have to do
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,is merely... *typing noises* just run it\Non the configuration file and it's gonna
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,do each step that we saw. Eventually I'm\Ngoing to stop it because it's going to
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,take several hours anyway. Eventually it\Nwill produce a result file that... I ran
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,this yesterday so you can see it here.\NThere is a lot going on here. I'm just
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,gonna go through some important like\Ninformation. So one thing that you can see
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,is that these are the border binaries that\NKaronte found. Now, there might be some
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,false positives. I'm not sure how many\Nthere are here. But as long as there are
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,no false negatives or the number is very\Nlow, it's fine. It's good. In this case,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,wait. Oh, I might have removed something.\NAll right, here, perfect. In this case,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,this guy httpd is a true positive, which\Nis the web server that we were talking
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,before. Then we have the BDG. In this\Ncase, we can see that Karonte found that
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,httpd communicates with two different\Nbinaries, fileaccess.cgi and cgibin. Then
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,we have information about the CPFs. For\Ninstance, here we can see that. Sorry. So
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,we can see here that httpd has 28 data\Nkeys. And that the semantics CPF found 27
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,of them and then there might be one other\Nhere or somewhere that I don't see .
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Anyway. And then we have a list of alerts.\NNow, thanks. Now, some of those may be
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,duplicates because of loops, so you can go\Nahead and inspect all of them manually.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,But I wrote a utility that you can use,\Nwhich is basically it's gonna filter out
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,all the loops for you. Now to remember how\NI called it. This guy? Yeah. And you can
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,see that in total it generated, the system\Ngenerated 6... 7... 8 alerts. So let's see
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,one of them. Oh, and I recently realized\Nthat the path that I'm reporting on the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,log. It's not the path from the setter\Nbinary to the getter binary, to the sink.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,But it's only related to the getter binary\Nup to the sink. I'm gonna fix this in the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,next days and report the whole paths.\NAnyway. So here we can see that the key
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,content type contains user input and it's\Npassed in an unsafe way to the sink
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,address at this address. Now. And the\Nbinary in question is called
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,fileaccess.cgi. So we can see what happens\Nthere. *keyboard noises* If you see here,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,we have a string copy that copies the\Ncontent of haystack to destination,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,haystack comes basically from this getenv.\NAnd if you see destination comes as
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,parameter from this function and return\Nand these and this by for it's as big as
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,0x68 bytes. And this turned out to be\Nactually a positive. OK. So in summary, we
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,presented a strategy to track data flow\Nacross different binaries. We evaluated
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,our system on 952 firmware samples and\Nsome takeaways. Analyzing firmware is not
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,easy and vulnerabilities persist. We found\Nout that firmware are made of
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,interconnected components and static\Nanalysis can still be used to efficiently
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,find vulnerabilities at scale and finding\Nthat communication is key for precision.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Here's a list of bibliography that I use\Nthroughout the presentation and I'm gonna
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,take questions.\N[filler, please remove in amara]
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,*applause*\N[filler, please remove in amara]
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Herald: So thank you, Nilo, for a very\Ninteresting talk. If you have questions,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,we have three microphones one, two and\Nthree. If you have a question, please go
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,head to the microphone and we'll take your\Nquestion. Yes. Microphone number two.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Q: Do you rely on imports from libc or\Nsomething like that or do you have some
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,issues with like statically linked\Nbinaries, stripped binaries or is it all
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,semantic analysis of a function?\NNilo: So. Okay. We use angr. So for
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,example, if you have an indirect call, we\Nuse angr to figure out, what's the target?
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,And to answer your question like if you\Nuse libc some CPFs do, for instance, then
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,environment CPF do any checks, if the\Nsetenv or getenv functions are called. But
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,also we use the semantic CPF, which\Nbasically in cases where information are
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,missing like there is no such thing as\Nlibc or some vendors reimplemented their
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,own functions. We use the CPF to actually\Ntry to understand the semantics of the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,function and understand if it's, for\Nexample, a custom setenv.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Q: Yeah, thanks.\NHerald: Microphone number three.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Q: In embedded environments you often have\Nalso that the getter might work on a DMA,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,some kind of vendor driver on a DMA. Are\Nyou considering this? And second part of
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the question, how would you then\Ndistinguish this from your generic IPC?
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Because I can imagine that they look very\Nsimilar in the actual code.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Nilo: So if I understand correctly your\Nquestion, you mention a case of MMIO where
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,some data is retrieved directly from some\Naddress in memory. So what we found is
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,that these addresses are usually hardcoded\Nsomewhere. So the vendor knows that, for
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,example, from this address A to this\Naddress B if some data is some data from
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,this peripheral. So when we find that some\Nhardcoded address, like we think that this
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,is like some read from some interesting\Ndata.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Q: Okay. And this would be also\Ndistinguishable from your sort of CPF, the
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,generic CPF would be distinguishable...\NNilo: Yeah. Yeah, yeah.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Q: ...from a DMA driver by using this\Nfixed address assuming.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Nilo: Yeah. That's what the semantic CPF\Ndoes, among the other things.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Q: Okay. Thank you.\NNilo: Sure.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Herald: Another question for microphone\Nnumber 3.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Q: What's the license for Karonte?\NNilo: Sorry?
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Q: I checked the software license, I\Nchecked the git repository and there is no
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,license like at all.\NNilo: That is a very good question. I
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,haven't thought about it yet. I will.\NHerald: Any more questions from here or
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,from the Internet? Okay. Then a big round\Nof applause to Nilo again for your talk.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,*postroll music*\N[filler, please remove in amara]
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Subtitles created by many many volunteers and\Nthe c3subtitles.de team. Join us, and help us!