The Bytecode Alliance: Building a secure, composable future for WebAssembly
> We have a vision of a WebAssembly ecosystem that is secure by default, fixing cracks in today’s software foundations. And based on advances rapidly emerging in the WebAssembly community, we believe we can make this vision real.
> WebAssembly can provide the kind of isolation that makes it safe to run untrusted code. We can have an architecture that’s like Unix’s many small processes, or like containers and microservices. But this isolation is much lighter weight, and the communication between them isn’t much slower than a regular function call. This means you can use them to wrap a single WebAssembly module instance, or a small collection of module instances that want to share things like memory among themselves.
TAA and other RIDL issues
> On Nov 12, 2019, we (VUSec) disclose TSX Asynchronous Abort (TAA), a new speculation-based vulnerability in Intel CPUs as well as other MDS-related issues, as described in our new RIDL addendum. In reality, this is no new vulnerability. We disclosed TAA (and other issues) as part of our original RIDL submission to Intel in Sep 2018. Unfortunately, the Intel PSIRT team missed our submitted proof-of-concept exploits (PoCs), and as a result, the original MDS mitigations released in May 2019 only partially addressed RIDL. You can read the full story below.
> On July 3, 2019, we finally learned that, to our surprise, the Intel PSIRT team had missed the PoCs from our Sep 29 submission, despite having awarded a bounty for it, explaining why Intel had failed to address - or even publicly acknowledge - many RIDL-class vulnerabilities on May 14, 2019.
When you have so many problems you’re paying out bounties without knowing what for...
TPM—Fail TPM meets Timing and Lattice Attacks
> We discovered timing leakage on Intel firmware-based TPM (fTPM) as well as in STMicroelectronics’ TPM chip. Both exhibit secret-dependent execution times during cryptographic signature generation. While the key should remain safely inside the TPM hardware, we show how this information allows an attacker to recover 256-bit private keys from digital signature schemes based on elliptic curves.
> This research shows that even rigorous testing as required by Common Criteria certification is not flawless and may miss attacks that have explicitly been checked for. The STMicroelectronics TPM chip is Common Criteria certified at EAL4+ for the TPM protection profiles and FIPS 140-2 certified at level 2, while the Intel TPM is certified according to FIPS 140-2. However, the certification has failed to protect the product against an attack that is considered by the protection profile.
children_tcache writeup and tcache overview
> This article is intended for the people who already have some knowledge about heap exploitation. If you already know some heap attacks on glibc<2.26 it’ll be fully understandable to you. But if you don’t, don’t worry - I’ve tried to make this post approachable for everyone with just basic knowledge. If you really know nothing about the topic, I recommend heap-exploitation.
> Tcache is an internal mechanism responsible for heap management. It was introduced in glibc 2.26 in the year 2017. It’s objective is to speed up the heap management. Older algorithms are not removed, but they are still used sometimes - for example for bigger chunks, or when an appropriate tcache bin is full. But heap exploitation with this mechanism is a lot easier due to a lack of heap integrity checks.
> Rolling forward 15 years, isogeny-based cryptography is another area with many technical subtleties, but is moving into the mainstream of cryptography. Once again, not everything that can be done with discrete logarithms can necessarily be done with isogenies. It is therefore not surprising to find papers that have issues with their security.
> It is probably time for an Isogenies for Cryptographers paper, but I don’t have time to write it. Instead, in this blog post I will mention several recent examples of incorrect papers. My hope is that these examples are instructional and will help prevent future mistakes. My intention is not to bring shame upon the authors.
Analyzing Android's CVE-2019-2215 (/dev/binder UAF)
> Over the past few weeks, those of you who frequent the DAY streams over on our Twitch may have seen me working on trying to understand the recent Android Binder Use-After-Free (UAF) published by Google’s Project Zero (p0). This bug is actually not new, the issue was discovered and fixed in the mainline kernel in February 2018, however, p0 discovered many popular devices did not receive the patch downstream. Some of these devices include the Pixel 2, the Huawei P20, and Samsung Galaxy S7, S8, and S9 phones. I believe many of these devices received security patches within the last couple weeks that finally killed the bug.
> After a few streams of poking around with a kernel debugger on a virtual machine (running Android-x86), and testing with a vulnerable Pixel 2, I’ve came to understand the exploit written by Jann Horn and Maddie Stone pretty well. Without an understanding of Binder (the binder_thread object specifically), as well as how Vectored I/O works, the exploit can be pretty confusing. It’s also quite clever how they exploited this issue, so I thought it would be cool to write up how the exploit works.
It’s super easy to bypass Android’s hidden API restrictions
> The API blacklist tracks who’s calling a function. If the source isn’t exempt, it crashes. In the first example, the source is the app. However, in the second example, the source is the system itself. Instead of using reflection to get what we want directly, we’re using it to tell the system to get what we want. Since the source of the call to the hidden function is the system, the blacklist doesn’t affect us anymore.
The call is coming from inside the system!
Gomium pwn challenge
> By doing the above we create a race where we access the implementation of X with the context of good that means if we “win” then inside the unsafe implementation f from the bad context will be used as a function pointer instead of a pointer to an integer. This will result in calling an arbitrary address (0x1337 in our case) which sounds quite promising.
Exploiting torn reads for fun and profit.
Security assessment techniques for Go projects
> With a better understanding of the root causes, we searched for existing tooling to help us quickly and effectively instrument client codebases. The result was a sample of static and dynamic open-source tools, including several that were Go-agnostic. To complement these tools, we also identified several compiler configurations that help with instrumentation.
Useful for developers who aren’t auditors as well.
'Mario Maker 2' Creators Are Using Cryptography to Make Impossible Levels
> A strange competition has popped up to create levels with audacious passcodes that you could spend a lifetime trying to guess.
Bypassing GitHub's OAuth flow
> What happens if we send an authenticated HEAD request to https://github.com/login/oauth/authorize? We’ve concluded that the router will treat it like a GET request, so it will get sent to the controller. But once it’s there, the controller will realize that it’s not a GET request, and so the request will be handled by the controller as if it was an authenticated POST request. As a result, GitHub will find the OAuth app specified in the request, and grant it access to the authenticated user’s data.
Help me, framework!
OpenTitan - open sourcing transparent, trustworthy, and secure silicon
> Today, along with our partners, we are excited to announce OpenTitan - the first open source silicon root of trust (RoT) project. OpenTitan will deliver a high-quality RoT design and integration guidelines for use in data center servers, storage, peripherals, and more. Open sourcing the silicon design makes it more transparent, trustworthy, and ultimately, secure.
> Light Commands is a vulnerability of MEMS microphones that allows attackers to remotely inject inaudible and invisible commands into voice assistants, such as Google assistant, Amazon Alexa, Facebook Portal, and Apple Siri using light.
> In our paper we demonstrate this effect, successfully using light to inject malicious commands into several voice controlled devices such as smart speakers, tablets, and phones across large distances and through glass windows.
Two New Tools that Tame the Treachery of Files
> Parsing is hard, even when a file format is well specified. But when the specification is ambiguous, it leads to unintended and strange parser and interpreter behaviors that make file formats susceptible to security vulnerabilities. What if we could automatically generate a “safe” subset of any file format, along with an associated, verified parser? That’s our collective goal in Dr. Sergey Bratus’s DARPA SafeDocs program.
> We’ve developed two new tools that take the pain out of parsing and make file formats safer:
> PolyFile: A polyglot-aware file identification utility with manually instrumented parsers that can semantically label the bytes of a file hierarchically; and
> PolyTracker: An automated instrumentation framework that efficiently tracks input file taint through the execution of a program.
U2F support in OpenSSH
> As of this morning, OpenSSH now has experimental U2F/FIDO support, with U2F being added as a new key type “firstname.lastname@example.org” or “ecdsa-sk” for short (the “sk” stands for “security key“).
Real-world measurements of structured-lattices and supersingular isogenies in TLS
> This is the third in a series of posts about running experiments on post-quantum confidentiality in TLS. The first detailed experiments that measured the estimated network overhead of three families of post-quantum key exchanges. The second detailed the choices behind a specific structured-lattice scheme. This one gives details of a full, end-to-end measurement of that scheme and a supersingular isogeny scheme, SIKE/p434. This was done in collaboration with Cloudflare, who integrated Microsoft’s SIKE code into BoringSSL for the tests, and ran the server-side of the experiment.
> Because optimised assembly implementations are labour-intensive to write, they were only available/written for AArch64 and x86-64. Because SIKE is computationally expensive, it wasn’t feasible to enable it without an assembly implementation, thus only AArch64 and x86-64 clients were included in the experiment and ARMv7 and x86 clients did not contribute to the results even if they were assigned to one of the experiment groups.
Potential bypass of Runas user restrictions
> When sudo is configured to allow a user to run commands as an arbitrary user via the ALL keyword in a Runas specification, it is possible to run commands as root by specifying the user ID -1 or 4294967295.
Interesting combination of circumstances.
Minerva: Lattice attacks strike again
> This page describes our discovery of a group of side-channel vulnerabilities in implementations of ECDSA/EdDSA in programmable smart cards and cryptographic software libraries. Our attack allows for practical recovery of the long-term private key. We have found implementations which leak the bit-length of the scalar during scalar multiplication on an elliptic curve. This leakage might seem minuscule as the bit-length presents a very small amount of information present in the scalar. However, in the case of ECDSA/EdDSA signature generation, the leaked bit-length of the random nonce is enough for full recovery of the private key used after observing a few hundreds to a few thousands of signatures on known messages, due to the application of lattice techniques.
How a double-free bug in WhatsApp turns to RCE
> In this blog post, I’m going to share about a double-free vulnerability that I discovered in WhatsApp for Android, and how I turned it into an RCE.
> Double-free vulnerability in DDGifSlurp in decoding.c in libpl_droidsonroids_gif