Threat Level: green Handler on Duty: Johannes Ullrich

SANS ISC: Linux kernel PRCTL local privilege escalation - SANS Internet Storm Center SANS ISC InfoSec Forums

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Linux kernel PRCTL local privilege escalation
This vulnerability enables an attacker to get elevated privileges on a local machine. There have been several exploits released and we can confirm that they work. We've tested this on unpatched SuSE and RedHat Enterprise Linux machines:

$ ./a.out

prctl() suidsafe exploit

(C) Julien TINNES

[+] Installed signal handler
[+] We are suidsafe dumpable!
[+] Malicious string forged
[+] Segfaulting child
[+] Waiting for exploit to succeed (~28 seconds)
[+] getting root shell

Debian also confirmed that this exploit was used on their recently compromised machine (

As all kernels 2.6.13 up to version and 2.6.16 before are affected, you should patch as soon as possible, even if you don't allow any local users on your machines. Remember that even a small vulnerability in a PHP script can allow local access, which then can be escalated with this exploit.

CVE for this vulnerability has also been issued:

Thanks to David Taylor for sending information about this to us.
I will be teaching next: Web App Penetration Testing and Ethical Hacking - SANS Pen Test Hackfest Europe 2022 - Berlin


403 Posts
ISC Handler
Jul 13th 2006

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