Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
===========================================================================
AUSCERT Security Bulletin
ASB-2009.1023
Linux Kernel NULL Pointer Dereference Vulnerability
22 July 2009
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: Linux kernel
Operating System: Linux variants
Impact/Access: Root Compromise -- Existing Account
Denial of Service -- Existing Account
Unauthorised Access -- Existing Account
Reduced Security -- Existing Account
Resolution: Patch
CVE Names: CVE-2009-1897 CVE-2009-1895
Member content until: Friday, August 21 2009
OVERVIEW
A number of vulnerabilities in the Linux kernel before 2.6.30.2 have
been reported which could allow local security bypass, code
execution or a denial of service.
IMPACT
(CVE-2009-1897)
A NULL pointer dereference in the tun_chr_poll() function allows
for a denial of service condition or the execution of arbitrary code
with root privileges if a local attacker were to open and poll a tun
device. [1]
(CVE-2009-1895)
A PER_CLEAR_ON_SETID mask in the the personality subsystem of the
Linux kernel does not include the ADDR_COMPAT_LAYOUT and MMAP_PAGE_ZERO
flags when executing a setuid or setgid program, allowing for memory
usage details to be procured. Local NULL pointer dereference attacks,
mmap_min_addr bypass and address space layout randomisation (ASLR)
circumvention. [2]
MITIGATION
A patch is available to download from the Linux Kernel Archives. [3]
REFERENCES
[1] Linux Kernel tun_chr_poll() code execution
http://xforce.iss.net/xforce/xfdb/51803
[2] Linux 2.6.30.2 Changelog
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=3c8a9c63d5fd738c261bd0ceece04d9c8357ca13
[3] The Linux Kernel Archives
http://kernel.org/
AusCERT has made every effort to ensure that the information contained
in this document is accurate. However, the decision to use the information
described is the responsibility of each user or organisation. The decision to
follow or act on information or advice contained in this security bulletin is
the responsibility of each user or organisation, and should be considered in
accordance with your organisation's site policies and procedures. AusCERT
takes no responsibility for consequences which may arise from following or
acting on information or advice contained in this security bulletin.
If you believe that your computer system has been compromised or attacked in
any way, we encourage you to let us know by completing the secure National IT
Incident Reporting Form at:
http://www.auscert.org.au/render.html?it=3192
===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072
Internet Email: auscert@auscert.org.au
Facsimile: (07) 3365 7031
Telephone: (07) 3365 4417 (International: +61 7 3365 4417)
AusCERT personnel answer during Queensland business hours
which are GMT+10:00 (AEST).
On call after hours for member emergencies only.
===========================================================================
-----BEGIN PGP SIGNATURE-----
Comment: http://www.auscert.org.au/render.html?it=1967
iD8DBQFKZmQoNVH5XJJInbgRAgGyAJ4zCLASSFSOvHijYyFSWIGusdCHOgCdGTME
I8qNsnUA8lmUAFkcDzq5kUc=
=hEfs
-----END PGP SIGNATURE-----