National Cyber-Alert System
Vulnerability Summary for CVE-2009-1897
Original release date:07/20/2009
Last revised:07/20/2009
Source:
US-CERT/NIST
Overview
The tun_chr_poll function in drivers/net/tun.c in the tun subsystem in the Linux kernel 2.6.30 and 2.6.30.1, when the -fno-delete-null-pointer-checks gcc option is omitted, allows local users to gain privileges via vectors involving a NULL pointer dereference and an mmap of /dev/net/tun, a different vulnerability than CVE-2009-1894.
Impact
CVSS Severity (version 2.0):
Impact Subscore:
10.0
Exploitability Subscore:
3.4
CVSS Version 2 Metrics:
Access Vector: Locally exploitable
Access Complexity: Medium
Authentication: Not required to exploit
Impact Type:Allows unauthorized disclosure of information; Allows unauthorized modification; Allows disruption of service
- Official Statement from Red Hat (07/21/2009)
-
Red Hat is aware of this issue and is tracking it via the following bug:
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=CVE-2009-1897
The flaw only affects the Red Hat Enterprise Linux 5.4 beta kernel, which includes a backport of the upstream bug fix introducing this flaw (git commit 33dccbb0). We will be addressing this flaw in a future update to the beta kernel. It is also possible to mitigate this flaw by ensuring that the permissions for /dev/net/tun is restricted to root only.
This issue does not affect any other released kernel in any Red Hat product.
References to Advisories, Solutions, and Tools
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External Source: VUPEN
Name: ADV-2009-1925
Type: Advisory; Patch Information
External Source: MISC
Name: http://grsecurity.net/~spender/cheddar_bay.tgz
Type: Patch Information
External Source: CONFIRM
Name: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=3c8a9c63d5fd738c261bd0ceece04d9c8357ca13
Type: Advisory; Patch Information
External Source: CONFIRM
Name: https://bugzilla.redhat.com/show_bug.cgi?id=512284
External Source: XF
Name: linux-kernel-tunchrpoll-code-execution(51803)
External Source: MLIST
Name: [oss-security] 20090717 Linux 2.6.30+/SELinux/RHEL5 test kernel 0day, exploiting the unexploitable
External Source: SECUNIA
Name: 35839
Type: Advisory
External Source: MLIST
Name: [linux-kernel] 20090706 Re: PROBLEM: tun/tap crashes if open() /dev/net/tun and then poll() it.
External Source: MISC
Name: http://isc.sans.org/diary.html?storyid=6820
External Source: MLIST
Name: [netdev] 20090409 Oops in tun: bisected to Limit amount of queued packets per device
External Source: FULLDISC
Name: 20090716 Re: Linux 2.6.30+/SELinux/RHEL5 test kernel 0day, exploiting the unexploitable
External Source: FULLDISC
Name: 20090716 Linux 2.6.30+/SELinux/RHEL5 test kernel 0day, exploiting the unexploitable