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TITLE:
Asterisk SIP INVITE Response User Enumeration Weakness

SECUNIA ADVISORY ID:
SA44452

VERIFY ADVISORY:
Secunia.com
http://secunia.com/advisories/44452/
Customer Area (Credentials Required)
https://ca.secunia.com/?page=viewadvisory&vuln_id=44452

RELEASE DATE:
2011-05-05

DISCUSS ADVISORY:
http://secunia.com/advisories/44452/#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/44452/

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=44452

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 has been discovered in Asterisk, which can be exploited by
malicious people to determine valid usernames.

The problem is that different responses are being sent when using a
valid or an invalid username in INVITE messages. This can be
exploited to determine valid usernames by sending specially crafted
INVITE messages.

The weakness is confirmed in version 1.8.3.3. Other versions may also
be affected.

SOLUTION:
There's currently no known effective workaround.

PROVIDED AND/OR DISCOVERED BY:
Francesco Tornieri

ORIGINAL ADVISORY:
http://packetstormsecurity.org/files/view/101011/asterisk-1.8.x-sip-username-enumeration.txt

OTHER REFERENCES:
Further details available in Customer Area:
http://secunia.com/products/corporate/EVM/

DEEP LINKS:
Further details available in Customer Area:
http://secunia.com/products/corporate/EVM/

EXTENDED DESCRIPTION:
Further details available in Customer Area:
http://secunia.com/products/corporate/EVM/

EXTENDED SOLUTION:
Further details available in Customer Area:
http://secunia.com/products/corporate/EVM/

EXPLOIT:
Further details available in Customer Area:
http://secunia.com/products/corporate/EVM/

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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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