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TITLE:
Asterisk Enumeration Weakness and Denial of Service Vulnerability

SECUNIA ADVISORY ID:
SA47059

VERIFY ADVISORY:
Secunia.com
http://secunia.com/advisories/47059/
Customer Area (Credentials Required)
https://ca.secunia.com/?page=viewadvisory&vuln_id=47059

RELEASE DATE:
2011-12-09

DISCUSS ADVISORY:
http://secunia.com/advisories/47059/#comments

AVAILABLE ON SITE AND IN CUSTOMER AREA:
 * Last Update
 * Popularity
 * Comments
 * Criticality Level
 * Impact
 * Where
 * Solution Status
 * Operating System / Software
 * CVE Reference(s)

http://secunia.com/advisories/47059/

ONLY AVAILABLE IN CUSTOMER AREA:
 * Authentication Level
 * Report Reliability
 * Secunia PoC
 * Secunia Analysis
 * Systems Affected
 * Approve Distribution
 * Remediation Status
 * Secunia CVSS Score
 * CVSS

https://ca.secunia.com/?page=viewadvisory&vuln_id=47059

ONLY AVAILABLE WITH SECUNIA CSI AND SECUNIA PSI:
 * AUTOMATED SCANNING

http://secunia.com/vulnerability_scanning/personal/
http://secunia.com/vulnerability_scanning/corporate/wsus_sccm_3rd_third_party_patching/

DESCRIPTION:
A weakness and vulnerability have been reported in Asterisk, which
can be exploited by malicious people to disclose certain system
information and cause a DoS (Denial of Service).

1) The weakness is caused due to Asterisk responding on different
ports for certain requests, which can be exploited to e.g. enumerate
SIP peers.

Successful exploitation requires that SIP endpoints with different
NAT settings are used.

2) The vulnerability is caused due to a NULL pointer dereference
error within the "handle_request_info()" function
(channels/chan_sip.c) when the "automon" feature is enabled (disabled
by default) and can be exploited to cause a crash by sending a
sequence of specially crafted SIP packets.

The weakness is reported in all Asterisk versions and the
vulnerability is reported in versions 1.6.2.x prior to 1.6.2.21 and
1.8.x prior to 1.8.7.2.

SOLUTION:
Update to versions 1.6.2.21 and 1.8.7.2 or apply patches. Follow the
vendor's instructions to prevent exploitation of weakness #1.

Further details available in Customer Area:
http://secunia.com/vulnerability_intelligence/

PROVIDED AND/OR DISCOVERED BY:
The vendor credits:
1) Ben Williams
2) Kristijan Vrban

ORIGINAL ADVISORY:
Asterisk:
http://downloads.asterisk.org/pub/security/AST-2011-013.html
http://downloads.asterisk.org/pub/security/AST-2011-014.html

OTHER REFERENCES:
Further details available in Customer Area:
http://secunia.com/vulnerability_intelligence/

DEEP LINKS:
Further details available in Customer Area:
http://secunia.com/vulnerability_intelligence/

EXTENDED DESCRIPTION:
Further details available in Customer Area:
http://secunia.com/vulnerability_intelligence/

EXTENDED SOLUTION:
Further details available in Customer Area:
http://secunia.com/vulnerability_intelligence/

EXPLOIT:
Further details available in Customer Area:
http://secunia.com/vulnerability_intelligence/

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About:
This Advisory was delivered by Secunia as a free service to help
private users keeping their systems up to date against the latest
vulnerabilities.

Subscribe:
http://secunia.com/advisories/secunia_security_advisories/

Definitions: (Criticality, Where etc.)
http://secunia.com/advisories/about_secunia_advisories/


Please Note:
Secunia recommends that you verify all advisories you receive by
clicking the link.
Secunia NEVER sends attached files with advisories.
Secunia does not advise people to install third party patches, only
use those supplied by the vendor.

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