Digital Rights Management (DRM) has been the bane of users since it was first introduced. Who remembers the battle it was getting Netflix running on Linux machines, or the literal legal fight over the DVD DRM decryption key? So the news from Signal, that DRM is finally being put to use to protect users is ironic.

The reason for this is Microsoft Recall — the AI powered feature that takes a snapshot of everything on the user’s desktop every few seconds. For whatever reason, you might want to exempt some windows from Recall’s memory window. It doesn’t speak well for Microsoft’s implementation that the easiest way for an application to opt out of the feature is to mark its window as containing DRM content. Signal, the private communications platform, is using this to hide from Recall and other screenshotting applications.

The Signal blogs warns that this may be just the start of agentic AI being rolled out with insufficient controls and permissions. The issue here isn’t the singularity or AI reaching sentience, it’s the same old security and privacy problems we’ve always had: Too much information being collected, data being shared without permission, and an untrusted actor having access to way more than it should.

Legacy Malware?

The last few stories we’ve covered about malicious code in open source repositories have featured how quickly the bad packages were caught. Then there’s this story about two-year-old malicious packages on NPM that are just now being found.

It may be that the reason these packages weren’t discovered until now, is that these packages aren’t looking to exfiltrate data, or steal bitcoin, or load other malware. Instead, these packages have a trigger date, and just sabotage the systems they’re installed on — sometimes in rather subtle ways. If a web application you were writing was experiencing intermittent failures, how long would it take you to suspect malware in one of your JavaScript libraries?

Where Are You Calling From?

Phone phreaking isn’t dead, it has just gone digital. One of the possibly apocryphal origins of phone phreaking was a toy bo’sun whistle in boxes of cereal, that just happened to play a 2600 Hz tone. More serious phreakers used more sophisticated, digital versions of the whistle, calling them blue boxes. In modern times, apparently, the equivalent of the blue box is a rooted Android phone. [Daniel Williams] has the story of playing with Voice over LTE (VoLTE) cell phone calls. A bug in the app he was using forced him to look at the raw network messages coming from O2 UK, his local carrier.

And those messages were weird. VoLTE is essentially using the Session Initiation Protocol (SIP) to handle cell phone calls as Voice over IP (VoIP) calls using the cellular data network. SIP is used in telephony all over the place, from desk phones to video conferencing solutions. SIP calls have headers that work to route the call, which can contain all sorts of metadata about the call. [Daniel] took a look at the SIP headers on a VoLTE call, and noticed some strange things. For one, the International Mobile Subscriber Identity (IMSI) and International Mobile Equipment Identity (IMEI) codes for both the sender and destination were available.

He also stumbled onto an interesting header, the Cellular-Network-Info header. This header encodes way too much data about the network the remote caller is connected to, including the exact tower being used. In an urban environment, that locates a cell phone to an area not much bigger than a city block. Together with leaking the IMSI and IMEI, this is a dangerous amount of information to leak to anyone on the network. [Daniel] attempted to report the issue to O2 in late March, and was met with complete silence. However, a mere two days after this write-up was published, on May 19th, O2 finally made contact, and confirmed that the issue had finally been resolved.

ARP Spoofing in Practice

TCP has an inherent security advantage, because it’s a stateful connection, it’s much harder to make a connection from a spoofed IP address. It’s harder, but it’s not impossible. One of the approaches that allows actual TCP connections from spoofed IPs is Address Resolution Protocol (ARP) poisoning. Ethernet switches don’t look at IP addresses, but instead route using MAC addresses. ARP is the protocol that distributes the MAC Address to IP mapping on the local network.

And like many protocols from early in the Internet’s history, ARP requests don’t include any cryptography and aren’t validated. Generally, whoever claims an IP address first wins, so the key is automating this process. And hence, enter NetImposter, a new tool specifically designed to automate this process, sending spoofed ARP packets, and establishing an “impossible” TCP connection.

Impossible RCE in SSH

Over two years ago, researchers at Qualsys discovered a pre-authentication double-free in OpenSSH server version 9.1. 9.2 was quickly released, and because none of the very major distributions had shipped 9.1 yet, what could have been a very nasty problem was patched pretty quietly. Because of the now-standard hardening features in modern Linux and BSD distributions, this vulnerability was thought to be impossible to actually leverage into Remote Code Execution (RCE).

If someone get a working OpenSSH exploit from this bug, I'm switching my main desktop to Windows 98 (this bug was discovered by a Windows 98 user who noticed sshd was crashing when trying to login to a Linux server!)

— Tavis Ormandy (@taviso) February 14, 2023

The bug was famously discovered by attempting to SSH into a modern Linux machine from a Windows 98 machine, and Tavis Ormandy claimed he would switch to Windows 98 on his main machine if someone did actually manage to exploit it for RCE. [Perri Adams] thought this was a hilarious challenge, and started working an exploit. Now we have good and bad news about this effort. [Perri] is pretty sure it is actually possible, to groom the heap and with enough attempts, overwrite an interesting pointer, and leak enough information in the process to overcome address randomization, and get RCE. The bad news is that the reward of dooming [Tavis] to a Windows 98 machine for a while wasn’t quite enough to be worth the pain of turning the work into a fully functional exploit.

But that’s where [Perri’s] OffensiveCon keynote took an AI turn. How well would any of the cutting-edge AIs do at finding, understanding, fixing, and exploiting this vulnerability? As you probably already guessed, the results were mixed. Two of the three AIs thought the function just didn’t have any memory management problems at all. Once informed of the problem, the models had more useful analysis of the code, but they still couldn’t produce any remotely useful code for exploitation. [Perri’s] takeaway is that AI systems are approaching the threshold of being useful for defensive programming work. Distilling what code is doing, helping in reverse engineering, and working as a smarter sort of spell checker are all wins for programmers and security researchers. But fortunately, we’re not anywhere close to a world where AI is developing and deploying exploitations.

Bits and Bytes

There are a pair of new versions of reverse engineering/forensic tools released very recently. Up first is Frida, a runtime debugger on steroids, that is celebrating its 17th major version release. One of the major features is migrating to pluggable runtime bridges, and moving away from strictly bundling them. We also have Volatility 3, a memory forensics framework. This isn’t the first Volatility 3 release, but it is the release where version three officially has parity with the version two of the framework.

The Foscam X5 security camera has a pair of buffer overflows, each of which can be leveraged to acieve arbitrary RCE. One of the proof-of-concepts has a very impressive use of a write-null-anywhere primitive to corrupt a return pointer, and jump into a ROP gadget. The concerning element of this disclosure is that the vendor has been completely unresponsive, and the vulnerabilities are still unaddressed.

And finally, one of the themes that I’ve repeatedly revisited is that airtight attribution is really difficult. [Andy Gill] walks us through just one of the many reasons that’s difficult. Git cryptographically signs the contents of a commit, but not the timestamps. This came up when looking through the timestamps from “Jia Tan” in the XZ compromise. Git timestamps can be trivially rewritten. Attestation is hard.

The sky is falling. Or more specifically, it was about to fall, according to the security community this week. The MITRE Corporation came within a hair’s breadth of running out of its contract to maintain the CVE database. And admittedly, it would be a bad thing if we suddenly lost updates to the central CVE database. What’s particularly interesting is how we knew about this possibility at all. An April 15 letter sent to the CVE board warned that the specific contract that funds MITRE’s CVE and CWE work was due to expire on the 16th. This was not an official release, and it’s not clear exactly how this document was leaked.

Many people made political hay out of the apparent imminent carnage. And while there’s always an element of political maneuvering when it comes to contract renewal, it’s worth noting that it’s not unheard of for MITRE’s CVE funding to go down to the wire like this. We don’t know how many times we’ve been in this position in years past. Regardless, MITRE has spun out another non-profit, The CVE Foundation, specifically to see to the continuation of the CVE database. And at the last possible moment, CISA has announced that it has invoked an option in the existing contract, funding MITRE’s CVE work for another 11 months.

Android Automatic Reboots

Mobile devices are in their most secure state right after boot, before the user password is entered to unlock the device for the first time. Tools like Cellebrite will often work once a device has been unlocked once, but just can’t exploit a device in the first booted state. This is why Google is rolling out a feature, where Android devices that haven’t been unlocked for three days will automatically reboot.

Once a phone is unlocked, the encryption keys are stored in memory, and it only takes a lock screen bypass to have full access to the device. But before the initial unlock, the device is still encrypted, and the keys are safely stored in the hardware security module. It’s interesting that this new feature isn’t delivered as an Android OS update, but as part of the Google Play Services — the closed source libraries that run on official Android phones.

4chan

4chan has been hacked. It turns out, running ancient PHP code and out-of-date libraries on a controversial site is not a great idea. A likely exploit chain has been described, though this should be considered very unofficial at this point: Some 4chan boards allow PDF uploads, but the server didn’t properly vet those files. A PostScript file can be uploaded instead of a PDF, and an old version of Ghostscript processes it. The malicious PostScript file triggers arbitrary code execution in Ghostscript, and a SUID binary is used to elevate privileges to root.

PHP source code of the site has been leaked, and the site is still down as of the time of writing. It’s unclear how long restoration will take. Part of the fallout from this attack is the capture and release of internal discussions, pictures of the administrative tools, and even email addresses from the site’s administration.

Recall is Back

Microsoft is back at it, working to release Recall in a future Windows 11 update. You may remember our coverage of this, castigating the security failings, and pointing out that Recall managed to come across as creepy. Microsoft wisely pulled the project before rolling it out as a full release.

If you’re not familiar with the Recall concept, it’s the automated screenshotting of your Windows machine every few seconds. The screenshots are then locally indexed with an LLM, allowing for future queries to be run against the data. And once the early reviewers got over the creepy factor, it turns out that’s genuinely useful sometimes.

On top of the security hardening Microsoft has already done, this iteration of Recall is an opt-in service, with an easy pause button to temporarily disable the snapshot captures. This is definitely an improvement. Critics are still sounding the alarm, but for a much narrower problem: Recall’s snapshots will automatically extract information from security focused applications. Think about Signal’s disappearing messages feature. If you send such a message to a desktop user, that has Recall enabled, the message is likely stored in that user’s Recall database.

It seems that Microsoft has done a reasonably good job of cleaning up the Recall feature, particularly by disabling it by default. It seems like the privacy issues could be furthered addressed by giving applications and even web pages a way to opt out of Recall captures, so private messages and data aren’t accidentally captured. As Recall rolls out, do keep in mind the potential extra risks.

16,000 Symlinks

It’s been recently discovered that over 16,000 Fortinet devices are compromised with a trivial backdoor, in the form of a symlink making the root filesystem available inside the web-accessible language folder. This technique is limited to devices that have the SSL VPN enabled. That system exposes a web interface, with multiple translation options. Those translation files live in a world-accessible folder on the web interface, and it makes for the perfect place to hide a backdoor like this one. It’s not a new attack, and Fortinet believes the exploited devices have harbored this backdoor since the 2023-2024 hacking spree.

Vibes

We’re a little skeptical on the whole vibe coding thing. Our own [Tyler August] covered one of the reasons why. LLMs are likely to hallucinate package names, and vibe coders may not check closely, leading to easy typosquatting (LLMsquatting?) attacks. Figure out the likely hallucinated names, register those packages, and profit.

But what about Vibe Detections? OK, we know, letting an LLM look at system logs for potentially malicious behavior isn’t a new idea. But [Claudio Contin] demonstrates just how easy it can be, with the new EDV tool. Formally not for production use, this new gadget makes it easy to take Windows system events, and feed them into Copilot, looking for potentially malicious activity. And while it’s not perfect, it did manage to detect about 40% of the malicious tests that Windows Defender missed. It seems like LLMs are going to stick around, and this might be one of the places they actually make sense.

Bits and Bytes

Apple has pushed updates to their entire line, fixing a pair of 0-day vulnerabilities. The first is a wild vulnerability in CoreAudio, in that playing audio from a malicious audio file can lead to arbitrary code execution. The chaser is the flaw in the Pointer Authentication scheme, that Apple uses to prevent memory-related vulnerabilities. Apple has acknowledged that these flaws were used in the wild, but no further details have been released.

The Gnome desktop has an interesting problem, where the yelp help browser can be tricked into reading the contents of arbitrary filesystem files. Combined with the possibility of browser links automatically opening in yelp, this makes for a much more severe problem than one might initially think.

And for those of us following along with Google Project Zero’s deep dive into the Windows Registry, part six of that series is now available. This installment dives into actual memory structures, as well as letting us in on the history of why the Windows registry is called the hive and uses the 0xBEE0BEE0 signature. It’s bee themed, because one developer hated bees, and another developer thought it would be hilarious.