Feeds

Bug exposes eight years of Linux kernel

Passes it's-not-crying-wolf test

Next gen security for virtualised datacentres

Linux developers have issued a critical update for the open-source OS after researchers uncovered a vulnerability in its kernel that puts most versions built in the past eight years at risk of complete takeover.

The bug involves the way kernel-level routines such as sock_sendpage react when they are left unimplemented. Instead of linking to a corresponding placeholder, (for example, sock_no_accept), the function pointer is left uninitialized. Sock_sendpage doesn't always validate the pointer before dereferencing it, leaving the OS open to local privilege escalation that can completely compromise the underlying machine.

"Since it leads to the kernel executing code at NULL, the vulnerability is as trivial as it can get to exploit," security researcher Julien Tinnes writes here. "An attacker can just put code in the first page that will get executed with kernel privileges."

Tinnes and fellow researcher Tavis Ormandy released proof-of-concept code that they said took just a few minutes to adapt from a previous exploit they had. They said all 2.4 and 2.6 versions since May 2001 are affected.

Security researchers not involved in the discovery were still studying the advisory at time of writing, but at least one of them said it appeared at first blush to warrant immediate action.

"This passes my it's-not-crying-wolf test so far," said Rodney Thayer, CTO of security research firm Secorix. "If I had some kind of enterprise-class Linux system like a Red Hat Enterprise Linux...I would really go check and see if this looked like it related, and if my vendor was on top of it and did I need to get a kernel patch."

This is the second time in less than a month that a serious security vulnerability has been reported in the Linux kernel. In mid July, a researcher alerted Linux developers to a separate "NULL pointer dereference" bug that put newer versions at risk of complete compromise. The bug, which was located in several parts of the kernel, attracted plenty of notice because it bit even when SELinux, or Security-Enhanced Linux, implementations were running.

More about the latest vulnerability is here, and additional details about the patch are here. ®

The essential guide to IT transformation

More from The Register

next story
Goog says patch⁵⁰ your Chrome
64-bit browser loads cat vids FIFTEEN PERCENT faster!
Chinese hackers spied on investigators of Flight MH370 - report
Classified data on flight's disappearance pinched
NIST to sysadmins: clean up your SSH mess
Too many keys, too badly managed
Scratched PC-dispatch patch patched, hatched in batch rematch
Windows security update fixed after triggering blue screens (and screams) of death
Researchers camouflage haxxor traps with fake application traffic
Honeypots sweetened to resemble actual workloads, complete with 'secure' logins
prev story

Whitepapers

Top 10 endpoint backup mistakes
Avoid the ten endpoint backup mistakes to ensure that your critical corporate data is protected and end user productivity is improved.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Backing up distributed data
Eliminating the redundant use of bandwidth and storage capacity and application consolidation in the modern data center.
The essential guide to IT transformation
ServiceNow discusses three IT transformations that can help CIOs automate IT services to transform IT and the enterprise
Next gen security for virtualised datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.