This Week In Security: MOAB, Microsoft, And Printers

January 26, 2024 by 15 Comments

This week, news has broken of the Mother of All Breaches, MOAB. It’s 12 terabytes and 26 billion records, averaging about 500 bytes each. Now note that a record here is likely not a discrete email address, but simply a piece of data — a row on the database.

Now before we all lose our minds over this, there’s an important detail to take note of: These aren’t new leaks. This is a compilation of leaks, and as far as researchers have checked, there aren’t any new leaks disclosed here. This was someone’s database of accumulated leak data, accidentally re-leaked via an unsecured database. [Troy Hunt] goes so far as to speculate that it could be from a breach search service, which sounds pretty plausible.

There was yet another release of credentials late last week that hasn’t attracted as much attention, but seems to represent a much bigger issue. The Naz.api data set isn’t a breach where a company was hacked, and their entire user database was stolen. Instead, this one is combination of a credential stuffing list and stealer logs.

Credential stuffing is basically a smarter brute force attack, where the credentials from one breach are tried on multiple other sites. Such a list is just the results where guesses were successful. The really interesting bit is that this dataset seems to include stealer logs. Put simply, that’s the results of malware that scrapes victim machines for credentials.

Naz.api has over 70 million unique email addresses, and it looks like about a third of them are new, at least according to the Haveibeenpwned dataset. Now that’s significant, though not really worthy of the MOAB title, either. Continue reading “This Week In Security: MOAB, Microsoft, And Printers” →

This Week In Security: Gitlab, VMware, And PixeFAIL

January 19, 2024 by 3 Comments

There’s a Gitlab vulnerability that you should probably pay attention to. Tracked as CVE-2023-7028, this issue allows an attacker to specify a secondary email during a the password reset request. Only one email has to match the one on record, but the password reset link gets sent to both emails. Yikes!

What makes this worse is there is already a Proof of Concept (PoC) released, and it’s a trivial flaw. In an HTTP/S post containing the password reset request, just include two email addresses. Thankfully, a fix is already out. Versions 16.7.2, 16.6.4, and 16.5.6 contain this patch, as well as fixes for a flaw that allowed sneaking unauthorized changes into a previously approved merge request, and an issue with Slack and Mattermost where slash commands could be spoofed.

VMware

We don’t want to over-dramatise this vulnerability, but VMware is calling it an emergency. This one affects VMware vRealize and Aria Automation. According to the the CVSS calculator, it’s a low complexity network flaw, but does require at least some privileges. Hopefully more information will come out about this vulnerability, but for now that’s about all we know.

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This Week In Security: AI Is Terrible, Ransomware Wrenches, And Airdrop

January 12, 2024 by 8 Comments

So first off, go take a look at this curl bug report. It’s a 8.6 severity security problem, a buffer overflow in websockets. Potentially a really bad one. But, it’s bogus. Yes, a strcpy call can be dangerous, if there aren’t proper length checks. This code has pretty robust length checks. There just doesn’t seem to be a vulnerability here.

OK, so let’s jump to the punch line. This is a bug report that was generated with one of the Large Language Models (LLMs) like Google Bard or ChatGPT. And it shouldn’t be a surprise. There are some big bug bounties that are paid out, so naturally people are trying to leverage AI to score those bounties. But as [Daniel Stenberg] point out, LLMs are not actually AI, and the I in LLM stands for intelligence.

There have always been vulnerability reports of dubious quality, sent by people that either don’t understand how vulnerability research works, or are willing to waste maintainer time by sending in raw vulnerability scanner output without putting in any real effort. What LLMs do is provide an illusion of competence that takes longer for a maintainer to wade through before realizing that the claim is bogus. [Daniel] is more charitable than I might be, suggesting that LLMs may help with communicating real issues through language barriers. But still, this suggests that the long term solution may be “simply” detecting LLM-generated reports, and marking them as spam. Continue reading “This Week In Security: AI Is Terrible, Ransomware Wrenches, And Airdrop” →

This Week In Security: Bitwarden, Reverse RDP, And Snake

January 5, 2024 by 10 Comments

This week, we finally get the inside scoops on some old stories, starting with the Bitwarden Windows Hello problem from last year. You may remember, Bitwarden has an option to use Windows Hello as a vault unlock option. Unfortunately, the Windows credential API doesn’t actually encrypt credentials in a way that requires an additional Windows Hello verification to unlock. So a derived key gets stored to the credential manager, and can be retrieved through a simple API call. No additional biometrics needed. Even with the Bitwarden vault locked and application closed.

There’s another danger, that doesn’t even require access to the the logged-in machine. On a machine that is joined to a domain, Windows backs up those encryption keys to the Domain Controller. The encrypted vault itself is available on a domain machine over SMB by default. A compromised domain controller could snag a bitwarden vault without ever even running code on the target machine. The good news is that this particular problem with Bitwarden and Windows Hello is now fixed, and has been since version 2023.10.1.

Reverse RDP Exploitation

We normally think about the Remote Desktop Protocol as dangerous to expose to the internet. And it is. Don’t put your RDP service online. But reverse RDP is the idea that it might also be dangerous to connect an RDP client to a malicious server. And of course, multiple RDP implementations have this problem. There’s rdesktop, FreeRDP, and Microsoft’s own mstsc that all have vulnerabilities relating to reverse RDP.

The technical details here aren’t terribly interesting. It’s all variations on the theme of not properly checking remote data from the server, and hence either reading or writing past internal buffers. This results in various forms of information leaks and code executions problems. What’s interesting is the different responses to the findings, and then [Eyal Itkin]’s takeaway about how security researchers should approach vulnerability disclosure.

So first up, Microsoft dismissed a vulnerability as unworthy of servicing. And then proceeded to research it internally, and present it as a novel attack without properly attributing [Eyal] for the original find. rdesktop contained quite a few of these issues, but were able to fix the problem in a handful of months. FreeRDP fixed some issues right away, in what could be described as a whack-a-mole style process, but a patch was cooked up that would actually address the problem at a deeper level: changing an API value from the unsigned size_t to a signed ssize_t. That change took a whopping 2 years to actually make it out to the world in a release. Why so long? Continue reading “This Week In Security: Bitwarden, Reverse RDP, And Snake” →

This Week In Security: Triangulation, ProxyCommand, And Barracuda

December 29, 2023 by 6 Comments

It’s not every day we get to take a good look inside a high-level exploit chain developed by an unnamed APT from the western world. But thanks to some particularly dedicated researchers at Kaspersky, which just happens to be headquartered in Moscow, that’s exactly what we have today. The name Operation Triangulation was picked, based off part of the device fingerprinting code that rendered a yellow triangle on an HTML canvas.

The entire talk is available, given this week at the 37th Chaos Communication Congress, 37c3. The exploit starts with an iMessage attachment, delivered silently, that exploits an undocumented TrueType font instruction. Looking at the source code implies that it was a copy-paste error where a programmer didn’t quite get the logic right for a pointer calculation. That vulnerability gives a memory write primitive that pivots into code execution. What’s particularly interesting is that Apple silently fixed this bug January 2023, and didn’t make any public statements. Presumably there were an uptick of crash logs that pointed to this problem, but didn’t conclusively show attempted exploitation.

The exploits then moves to using NSExpression as a next stage. NSExpression is an ugly way to write code, but it does allow the exploit chain to get to the next stage, running JavaScript as an application, without Just In Time compilation. The JS payload is quite a beast, weighing in at 11,000 lines of obfuscated code. It manages to call native APIs directly from JS, which then sets up a kernel exploit. This is multiple integer overflow flaws that result in essentially arbitrary system memory reads and writes. Continue reading “This Week In Security: Triangulation, ProxyCommand, And Barracuda” →

A RISC-V Security Key

December 26, 2023 by 6 Comments

The TKey is a RISC-V-based security key that plugs into a USB port. The device has a number of features, including a device-specific serial number, RAM scrambling, and a monitor that kills the CPU in the event of access to protected memory. There is also an FPGA that, on the end-user version, is locked down. This prevents you from changing the core features and the unique ID number for the device.

As part of the start-up code, the device calculates a hash of the application and merges it with the device ID and, potentially, a user-defined secret. If this number matches a previous calculation, it is reasonably certain that nothing has changed between the times of the calculations.

Continue reading “A RISC-V Security Key” →

This Week In Security: Terrapin, Seized Unseized, And Autospill

December 22, 2023 by 5 Comments

There’s a new SSH vulnerability, Terrapin (pdf paper), and it’s got the potential to be nasty — but only in an extremely limited circumstance. To understand the problem, we have to understand what SSH is designed to do. It replaces telnet as a tool to get a command line shell on a remote computer. Telnet send all that text in the clear, but SSH wraps it all inside a public-key encrypted tunnel. It was designed to safely negotiate an unfriendly network, which is why SSH clients are so explicit about accepting new keys, and alerting when a key has changed.

SSH uses a sequence counter to detect Man-in-the-Middle (MitM) shenanigans like packet deletion, replay, or reordering. That sequence isn’t actually included in the packet, but is used as part of the Message Authentication Check (MAC) of several encryption modes. This means that if a packet is removed from the encrypted tunnel, the MAC fails on the rest of the packets, triggering a complete connection reset. This sequence actually starts at zero, with the first unencrypted packet sent after the version banners are exchanged. In theory, this means that an attacker fiddling with packets in the pre-encryption phase will invalidate the entire connection as well. There’s just one problem.

The innovation from the Terrapin researchers is that an attacker with MitM access to the connection can insert a number of benign messages in the pre-encryption phase, and then silently drop the first number of messages in the encrypted phase. Just a little TCP sequence rewriting for any messages between, and neither the server nor client can detect the deception. It’s a really interesting trick — but what can we do with it?

For most SSH implementations, not much. The 9.6 release of OpenSSH addresses the bug, calling it cryptographically novel, but noting that the actual impact is limited to disabling some of the timing obfuscation features added to release 9.5.

Continue reading “This Week In Security: Terrapin, Seized Unseized, And Autospill” →