Author: Jonathan Bennett

449 Articles

This Week In Security: Rsync, SSO, And Pentesting Mushrooms

January 17, 2025 by 11 Comments

Up first, go check your machines for the rsync version, and your servers for an exposed rsync instance. While there are some security fixes for clients in release 3.4.0, the buffer overflow in the server-side rsync daemon is the definite standout. The disclosure text includes this bit of nightmare fuel: “an attacker only requires anonymous read access to a rsync server, such as a public mirror, to execute arbitrary code on the machine the server is running on.”

A naive search on Shodan shows a whopping 664,955 results for rsync servers on the Internet. Red Hat’s analysis gives us a bit more information. The checksum length is specified by the remote client, and an invalid length isn’t properly rejected by the server. The effect is that an attacker can write up to 48 bytes into the heap beyond the normal checksum buffer space. The particularly dangerous case is also the default: anonymous access for file retrieval. Red Hat has not identified a mitigation beyond blocking access.

If you run servers or forward ports, it’s time to look at ports 873 and 8873 for anything listening. And since that’s not the only problem fixed, it’s really just time to update to rsync 3.4.0 everywhere you can. While there aren’t any reports of this being exploited in the wild, it seems like attempts are inevitable. As rsync is sometimes used in embedded systems and shipped as part of appliances, this particular bug threatens to have quite the long tail. Continue reading “This Week In Security: Rsync, SSO, And Pentesting Mushrooms” →

This Week In Security: Backdoored Backdoors, Leaking Cameras, And The Safety Label

January 10, 2025 by 3 Comments

The mad lads at watchTowr are back with their unique blend of zany humor and impressive security research. And this time, it’s the curious case of backdoors within popular backdoors, and the list of unclaimed domains that malicious software would just love to contact.

OK, that needs some explanation. We’re mainly talking about web shells here. Those are the bits of code that get uploaded to a web server, that provide remote access to the computer. The typical example is a web application that allows unrestricted uploads. If an attacker can upload a PHP file to a folder where .php files are used to serve web pages, accessing that endpoint runs the arbitrary PHP code. Upload a web shell, and accessing that endpoint gives a command line interface into the machine.

The quirk here is that most attackers don’t write their own tools. And often times those tools have special, undocumented features, like loading a zero-size image from a .ru domain. The webshell developer couldn’t be bothered to actually do the legwork of breaking into servers, so instead added this little dial-home feature, to report on where to find all those newly backdoored machines. Yes, many of the popular backdoors are themselves backdoored.

This brings us to what watchTowr researchers discovered — many of those backdoor domains were either never registered, or the registration has been allowed to expire. So they did what any team of researchers would do: Buy up all the available backdoor domains, set up a logging server, and just see what happens. And what happened was thousands of compromised machines checking in at these old domains. Among the 4000+ unique systems, there were a total of 4 .gov. domains from governments in Bangladesh, Nigeria, and China. It’s an interesting romp through old backdoors, and a good look at the state of still-compromised machines.

Continue reading “This Week In Security: Backdoored Backdoors, Leaking Cameras, And The Safety Label” →

FLOSS Weekly Episode 815: You Win Some, You Lose Some

January 8, 2025 by 2 Comments

This week, Jonathan Bennett and Randal chat with Matija Šuklje about Open Source and the Law! How do Open Source projects handle liability, what should a Contributor License Agreement (CLA) look like, and where can an individual or project turn for legal help?

Continue reading “FLOSS Weekly Episode 815: You Win Some, You Lose Some” →

This Week In Security: IOCONTROL, (Location) Leaking Cars, And Passkeys

January 3, 2025 by 11 Comments

Claroty’s TEAM82 has a report on a new malware strain, what they’re calling IOCONTROL. It’s a Linux malware strain aimed squarely at embedded devices. One of the first targets of this malware, surprisingly, is the Iraeli made Orpak gas station pumps. There’s a bit of history here, as IOCONTROL is believed to be used by CyberAv3ngers, a threat actor aligned with Iran. In 2023 a group aligned with Israel claimed to have compromised the majority of the gas stations in Iran. IOCONTROL seems to have been deployed as retribution.

There are a few particularly interesting aspects of this malware, and how TEAM82 went about analyzing it. The first is that they used unicorn to emulate the obscure ARM platform in question. This was quite an adventure, as they were running the malicious binary without the normal Linux OS under it, and had to re-implement system calls to make execution work. The actual configuration data was encrypted as the data section of the executable, presumably to avoid simple string matching detection and analysis.

Then to communicate with the upstream command and control infrastructure, the binary first used DNS-Over-HTTPS to resolve DNS addresses, and then used the MQTT message protocol for actual communications. Once in place, it has the normal suite of capabilities, like code execution, cleanup, lateral scanning, etc. An interesting speculation is that the level of control this malware had over these gas pumps, it was in a position to steal credit card information. This malware family isn’t limited to gas pumps, either, as it’s been spotted in IoT and SCADA devices from a whole host of vendors. Continue reading “This Week In Security: IOCONTROL, (Location) Leaking Cars, And Passkeys” →

This Week In Security: License Plates, TP-Link, And Attacking Devs

December 27, 2024 by 22 Comments

We’re covering two weeks of news today, which is handy, because the week between Christmas and New Years is always a bit slow.

And up first is the inevitable problem with digital license plates. Unless very carefully designed to be bulletproof, they can be jailbroken, and the displayed number can be changed. And the Reviver plates were definitely not bulletproof, exposing a physical programming port on the back of the plate. While it’s not explicitly stated, we’re guessing that’s a JTAG port, given that the issue is considered unpatchable, and the port allows overwriting the firmware. That sort of attack can be hardened against with signed firmware, and using an MCU that enforces it.

This does invite comparisons to the James Bond revolving license plate — and that comparison does put the issue into context. It’s always been possible to swap license plates. If someone really wants to cause mischief, traditional plates can be stolen, or even faked. What a digital plate adds to the equation is the ability to switch plate numbers on the fly, without stopping or turning a screwdriver. Regardless, this seems like it will be an ongoing problem, as so many manufacturers struggle to create secure hardware.

Malicious RDP

There’s a clever attack, that uses Microsoft’s Remote Desktop Protocol (RDP), to give away way too much control over a desktop. That’s accomplished by sending the target a .rdp file that shares local resources like the clipboard, filesystem, and more. What’s new is that it seems this theoretical attack has now shown up in the wild.

The attack campaign has been attributed to APT29, CozyBear, a threat actor believed to be associated with Russia’s Foreign Intelligence Service. This attribution tracks with the victims of choice, like government, research, and Ukrainian targets in particular. To escape detection, the malicious RDP endpoints are set up behind RDP proxies, running on services like AWS. The proxies and endpoints are accessed through TOR and other anonymous proxies. The .rdp files were spread via spear-phishing emails sent through compromised mail servers. The big push, with about 200 targets, was triggered on October 22nd. Researchers at TrendMicro believe this was the end of a targeted campaign. The idea being that at the end of the campaign, it no longer matters if the infrastructure and methods get discovered, so aim for maximum impact.

Free* Mcdonalds?

Here we learn that while McDonald’s USA dosn’t have a bug bounty program, McDonald’s India does — and that’s why researcher [Eaton Zveare] looked there. And found a series of Broken Object Level Authorization (BOLA) bugs. That’s a new term to this column, but a concept we’ve talked about before. BOLA vulnerabilities happen when a service validates a user’s authentication token, but doesn’t properly check that the user is authorized to access the specific resources requested.

In the McDonald’s case, any user of the web app is issued a guest JWT token, and that token is then valid to access any Order ID in the system. That allows some interesting fun, like leaving reviews on other users’ orders, accessing delivery maps, and getting copies of receipts. But things got really interesting when creating an account, and then ordering food. A hidden, incomplete password login page allowed breaking the normal user verification flow, and creating an account. Then after food is added to the cart, the cart can be updated to have a total price of a single rupee, about the value of a penny.

This research earned [Eaton] a $240 Amazon gift card, which seems a little stingy, but the intent behind the gesture is appreciated. The fixes landed just over 2 months after reported, and while [Eaton] notes that this is slower than some companies, it’s significantly faster than some of the less responsive vendors that we’ve seen.

Banning TP-Link

The US Government has recently begun discussing a plan to ban TP-Link device purchases in the United States. The reported reason is that TP-Link devices have shipped with security problems. One notable example is a botnet that Microsoft has been tracking, that primarily consists of TP-Link devices.

This explanation rings rather hollow, particularly given the consistent security failings from multiple vendors that we’ve covered on this very column over the years. Where it begins to make more sense is when considered in light of the Chinese policy that all new vulnerabilities must first be reported to the Chinese government, and only then can fixes be rolled out. It suggests that the US Commerce Department suspects that TP-Link is still following this policy, even though it’s technically now a US company.

I’m no stranger to hacking TP-Link devices. Many years ago I wrote a simple attack to put the HTTPD daemon on TP-Link routers into debug mode, by setting the wifi network name. Because the name was used to build a command run with bash, it was possible to do command injection, build a script in the device’s /tmp space, and then execute that script. Getting to debug mode allowed upgrading to OpenWRT on the device. And that just happens to be my advice for anyone still using TP-Link hardware: install OpenWRT on it.

Developers Beware

We have two separate instances of malware campaigns directly targeting developers. The first is malicious VSCode extensions being uploaded to the marketplace. These fakes are really compelling, too, with lots of installs, reviews, and links back to the real pages. These packages seem to be droppers for malware payloads, and seem to be targeting cryptocurrency users.

If malware in your VSCode extensions isn’t bad enough, OtterCookie is a campaign believed to come from North Korea, spreading via fake job interviews. The interview asks a candidate to run a Node.js project, or install an npm package as part of prep. Those are malicious packages, and data stealers are deployed upon launch. Stay frosty, even on the job hunt.

Bits and Bytes

PHP has evolved over the years, but there are still a few quirks that might trip you up. One of the dangerous ones is tied up in $_SERVER['argv'], a quick way to test if PHP is being run from the command line, or on a server. Except, that relies on register_argc_argv set to off, otherwise query strings are enough to fool a naive application into thinking it’s running on the command line. And that’s exactly the footgun that caught Craft CMS with CVE-2024-56145.

Australia may know something we don’t, setting 2030 as the target for retiring cryptography primitives that aren’t quantum resistant. That’s RSA, Elliptic-curve, and even SHA-256. It’s a bit impractical to think that those algorithms will be completely phased out by then, but it’s an interesting development to watch.

Fuzzing is a deep subject, and the discovery of 29 new vulnerabilities found in GStreamer is evidence that there’s still plenty to discover. This wasn’t coverage-guided fuzzing, where the fuzzer mutates the fuzzing input to maximize. Instead, this work uses a custom corpus generator, where the generator is aware of how valid MP4 files are structured.