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AUSCERT Security Bulletin
ASB-2009.1047
A vulnerability has been identified in Asterisk's SIP channel driver
11 August 2009
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AusCERT Security Bulletin Summary
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Product: Asterisk Open Source prior to versions 1.2.34, 1.4.26.1,
1.6.0.12, 1.6.1.4
Asterisk Business Edition prior to versions B.2.5.9,
C.2.4.1, C.3.1
s800i Asterisk Appliance prior to version 1.3.0.3
Operating System: UNIX variants (UNIX, Linux, OSX)
Impact/Access: Denial of Service -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2009-2726
Member content until: Thursday, September 10 2009
OVERVIEW
A vulnerability has been identified in Asterisk Open Source prior to
versions 1.2.34, 1.4.26.1, 1.6.0.12, 1.6.1.4, Asterisk Business Edition
prior to versions B.2.5.9, C.2.4.1, C.3.1 and s800i Asterisk Appliance
prior to version 1.3.0.3. [1]
IMPACT
The vendor has provided the following description of the vulnerability:
"On certain implementations of libc, the scanf family of functions uses
an unbounded amount of stack memory to repeatedly allocate string
buffers prior to conversion to the target type. Coupled with Asterisk's
allocation of thread stack sizes that are smaller than the default, an
attacker may exhaust stack memory in the SIP stack network thread by
presenting excessively long numeric strings in various fields." [1]
MITIGATION
The vendor recommends upgrading to the latest version of Asterisk. [1]
REFERENCES
[1] Asterisk Project Security Advisory - AST-2009-005
http://downloads.asterisk.org/pub/security/AST-2009-005.html
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
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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.
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