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TITLE:
Asterisk Security Bypass and Denial of Service Vulnerabilities

SECUNIA ADVISORY ID:
SA44197

VERIFY ADVISORY:
Secunia.com
http://secunia.com/advisories/44197/
Customer Area (Credentials Required)
https://ca.secunia.com/?page=viewadvisory&vuln_id=44197

RELEASE DATE:
2011-04-23

DISCUSS ADVISORY:
http://secunia.com/advisories/44197/#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/44197/

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=44197

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:
Two vulnerabilities have been reported in Asterisk, which can be
exploited by malicious users to bypass certain security restrictions
and by malicious people to cause a DoS (Denial of Service).

1) The application does not properly limit the number of simultaneous
TCP connections to e.g. the Asterisk Manager Interface, Skinny, SIP
over TCP, or the built in HTTP server, which can be exploited to
exhaust all available file descriptors and stop Asterisk from
processing new calls.

2) An error within the Asterisk Manager Interface when handling
"Originate" actions can be exploited to bypass a certain security
check and execute arbitrary shell commands by sending an "Originate"
action with both the "Async" and "Application" headers.

Successful exploitation requires that the attacker is an
authenticated manager user.

The vulnerabilities are reported in Asterisk Open Source prior to
versions 1.4.40.1, 1.6.1.25, 1.6.2.17.3, and 1.8.3.3 and Asterisk
Business Edition prior to version C.3.6.4

SOLUTION:
Update to a fixed version or apply patches. Set limits for
unauthenticated connections.

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

PROVIDED AND/OR DISCOVERED BY:
The vendor credits:
1) Tzafrir Cohen
2) Mark Murawski

ORIGINAL ADVISORY:
http://downloads.asterisk.org/pub/security/AST-2011-005.html
http://downloads.asterisk.org/pub/security/AST-2011-006.html

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.

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Please Note:
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Secunia NEVER sends attached files with advisories.
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