Author: Jonathan Bennett

533 Articles

This Week In Security: Medical Backdoors, Strings, And Changes At Let’s Encrypt

February 7, 2025 by 12 Comments

There are some interesting questions afoot, with the news that the Contec CMS8000 medical monitoring system has a backdoor. And this isn’t the normal debug port accidentally left in the firmware. The CISA PDF has all the details, and it’s weird. The device firmware attempts to mount an NFS share from an IP address owned by an undisclosed university. If that mount command succeeds, binary files would be copied to the local filesystem and executed.

Additionally, the firmware sends patient and sensor data to this same hard-coded IP address. This backdoor also includes a system call to enable the eth0 network before attempting to access the hardcoded IP address, meaning that simply disabling the Ethernet connection in the device options is not sufficient to prevent the backdoor from triggering. This is a stark reminder that in the firmware world, workarounds and mitigations are often inadequate. For instance, you could set the gateway address to a bogus value, but a slightly more sophisticated firmware could trivially enable a bridge or alias approach, completely bypassing those settings. There is no fix at this time, and the guidance is pretty straightforward — unplug the affected devices.

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This Week In Security: DeepSeek’s Oopsie, AI Tarpits, And Apple’s Leaks

January 31, 2025 by 8 Comments

DeepSeek has captured the world’s attention this week, with an unexpected release of the more-open AI model from China, for a reported mere $5 million training cost. While there’s lots of buzz about DeepSeek, here we’re interested in security. And DeepSeek has made waves there, in the form of a ClickHouse database unintentionally opened to the world, discovered by the folks from Wiz research. That database contained chat history and log streams, and API keys and other secrets by extension.

Finding this database wasn’t exactly rocket science — it reminds me of my biggest bug bounty win, which was little more than running a traceroute and a port scan. In this case it was domain and sub domain mapping, and a port scan. The trick here was knowing to try this, and then understanding what the open ports represented. And the ClickHouse database was completely accessible, leaking all sorts of sensitive data. Continue reading “This Week In Security: DeepSeek’s Oopsie, AI Tarpits, And Apple’s Leaks” →

This Week In Security: ClamAV, The AMD Leak, And The Unencrypted Power Grid

January 24, 2025 by 11 Comments

Cisco’s ClamAV has a heap-based buffer overflow in its OLE2 file scanning. That’s a big deal, because ClamAV is used to scan file attachments on incoming emails. All it takes to trigger the vulnerability is to send a malicious file through an email system that uses ClamAV.

The exact vulnerability is a string termination check that can fail to trigger, leading to a buffer over-read. That’s a lot better than a buffer overflow while writing to memory. That detail is why this vulnerability is strictly a Denial of Service problem. The memory read results in process termination, presumably a segfault for reading protected memory. There are Proof of Concepts (PoCs) available, but so far no reports of the vulnerability being used in the wild.
Continue reading “This Week In Security: ClamAV, The AMD Leak, And The Unencrypted Power Grid” →