Linux

48317 readers

844 users here now

From Wikipedia, the free encyclopedia

Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).

Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.

Rules

Posts must be relevant to operating systems running the Linux kernel. GNU/Linux or otherwise.
No misinformation
No NSFW content
No hate speech, bigotry, etc

Related Communities

Community icon by Alpár-Etele Méder, licensed under CC BY 3.0

founded 5 years ago

MODERATORS

[email protected]

522

backdoor in upstream xz/liblzma leading to ssh server compromise (www.openwall.com)

submitted 7 months ago by [email protected] to c/[email protected]

100 comments fedilink hide all child comments

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 3 points 7 months ago (2 children)

Is this only happened with SSH, or other network facing services using liblzma too?

[–] [email protected] 13 points 7 months ago (1 children)

We know that sshd is targeted but we don't know the full extent of the attack yet.

[–] [email protected] 2 points 7 months ago* (last edited 7 months ago)

Also, even aside from the attack code here having unknown implications, the attacker made extensive commits to liblzma over quite a period of time, and added a lot of binary test files to the xz repo that were similar to the one that hid the exploit code here. He also was signing releases for some time prior to this, and could have released a signed tarball that differed from the git repository, as he did here. The 0.6.0 and 0.6.1 releases were contained to this backdoor aimed at sshd, but it's not impossible that he could have added vulnerabilities prior to this. Xz is used during the Debian packaging process, so code he could change is active during some kind of sensitive points on a lot of systems.

It is entirely possible that this is the first vulnerability that the attacker added, and that all the prior work was to build trust. But...it's not impossible that there were prior attacks.

[–] [email protected] 7 points 7 months ago* (last edited 7 months ago)

The malicious code attempts to hook in to libcrypto, so potentially other services that use libcrypto could be affected too. I don't think extensive research has been done on this yet.

SSH doesn't even use liblzma. It's pulling in the malicious code via libsystemd, which does use liblzma.

Edit: "crypto" meaning cryptography of course, not cryptocurrency.