securitybreach Posted July 25, 2021 Share Posted July 25, 2021 Quote Some days, it doesn't rain, it pours. That's the case with Linux today. Not one, but two serious security holes have recently been exposed. First, there was a systemd bug which could easily knock out systems. Now there's this security hole in the Linux kernel's file system, which any user could use to take over a computer. Like I said, some days it just pours. The Qualys Research Team, which uncovered the file system bug, also discovered a size_t-to-int type conversion vulnerability in the Linux kernel's filesystem. This Linux security hole has been named Sequoia and it's been designated CVE-2021-33909. Doesn't sound like much, does it? Au contraire! It can be used against most Linux distributions in their default configurations. And, worse still, any -- I repeat, any -- unprivileged user can abuse it to gain root privileges. Here's how it works. We all use filesystems every day, but you probably don't think about how it works. Who, except for developers, does? In Linux's case, the file system interface is implemented in a three-layered architecture. There's the user interface layer; the file system implementation; and the storage device drivers. Within the Linux kernel's seq_file interface produces virtual files containing sequences of records. Each record must fit into a seq_file buffer. When it runs out of space, it's just enlarged by doubling its size. That's not a problem. You'll run out of memory long before you can hack the system with this. The problem shows up because this size_t variable is also passed to functions whose size argument is a signed 32-bit integer, not a size_t. And that, my friend, while a very large number, can be overrun........ https://www.zdnet.com/article/patch-now-linux-file-system-security-hole-dubbed-sequoia-can-take-over-systems/ 1 Quote Link to comment Share on other sites More sharing options...
sunrat Posted July 26, 2021 Share Posted July 26, 2021 Patched in Debian on July 20. Makes good clickbait though. https://forums.scotsnewsletter.com/index.php?/topic/22937-new-updates-debian/&do=findComment&comment=472177 Quote Link to comment Share on other sites More sharing options...
securitybreach Posted July 26, 2021 Author Share Posted July 26, 2021 It's not click bait at all. The article was written by Steven J. Vaughan-Nichols on the 21st. Quote Link to comment Share on other sites More sharing options...
securitybreach Posted July 26, 2021 Author Share Posted July 26, 2021 And like the article plainly states: This fix is also available in most Linux distributions now. So, if you've been sitting on your hands and not updating your Linux computers, it's time to get off them and start typing in patching commands. Quote Link to comment Share on other sites More sharing options...
sunrat Posted July 26, 2021 Share Posted July 26, 2021 13 minutes ago, securitybreach said: It's not click bait at all. The article was written by Steven J. Vaughan-Nichols on the 21st. Obviously it's not a trivial problem but so often vulnerabilities get overstated. I was just stirring a little to call it clickbait. 1 Quote Link to comment Share on other sites More sharing options...
V.T. Eric Layton Posted July 26, 2021 Share Posted July 26, 2021 Patched in Slackware on 21 July: Quote patches/packages/linux-4.4.276/*: Upgraded. These updates fix various bugs and security issues, including the recently announced local privilege escalation vulnerability in the filesystem layer (CVE-2021-33909). Quote Link to comment Share on other sites More sharing options...
V.T. Eric Layton Posted July 27, 2021 Share Posted July 27, 2021 Deleted my other post from just a few minutes ago, as it was a duplicate of this. 1 Quote Link to comment Share on other sites More sharing options...
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