TITLE:
Cisco Products TACACS+ Authentication Bypass

SECUNIA ADVISORY ID:
SA18904

VERIFY ADVISORY:
http://secunia.com/advisories/18904/

CRITICAL:
Less critical

IMPACT:
Security Bypass

WHERE:
>From remote

OPERATING SYSTEM:
Cisco Guard 5.x
http://secunia.com/product/8097/
Cisco Traffic Anomaly Detector 5.x
http://secunia.com/product/8095/

SOFTWARE:
Cisco Catalyst 6500/Cisco 7600 Router Anomaly Guard Module
http://secunia.com/product/8098/
Cisco Catalyst 6500/Cisco 7600 Router Traffic Anomaly Detector Module
http://secunia.com/product/8099/

DESCRIPTION:
A security issue has been reported in various Cisco products, which
can be exploited by malicious people to bypass certain security
restrictions.

The security issue is caused due to an error in TACACS+ (Terminal
Access Controller Access Control System Plus) and can be exploited to
bypass the user authentication and gain unauthorized access to the
devices.

Successful exploitation requires that TACACS+ authentication is
incompletely configured (i.e. the AAA command specifies TACACS+
authentication, but the configuration lacks the "tacacs-server host"
command).

The security issue affects the following products:
* Cisco Guard versions 5.0(1) and 5.0(3)
* Cisco Traffic Anomaly Detector versions 5.0(1) and 5.0(3)
* Anomaly Guard Module for the Cisco Catalyst 6500 switches/Cisco
7600 routers
* Traffic Anomaly Detector Module for the Cisco Catalyst 6500
switches/Cisco 7600 routers

NOTE: Versions prior to 5.0 and versions later than 5.0(3) are
unaffected.

SOLUTION:
Update to version 5.1(4) or later.

Software for the Cisco Guard appliance:
http://www.cisco.com/pcgi-bin/tablebuild.pl/cisco-ga-crypto.

Software for the Cisco Traffic Anomaly Detector appliance:
http://www.cisco.com/pcgi-bin/tablebuild.pl/cisco-ad-crypto.

Software for the Cisco Anomaly Guard Module:
http://www.cisco.com/pcgi-bin/tablebuild.pl/cisco-agm-crypto.

Software for the Cisco Anomaly Traffic Detector Module:
http://www.cisco.com/pcgi-bin/tablebuild.pl/cisco-adm-crypto

Configure TACACS+ authentication properly.

PROVIDED AND/OR DISCOVERED BY:
The vendor credits Gerrit Wenig.

ORIGINAL ADVISORY:
http://www.cisco.com/warp/public/707/cisco-sa-20060215-guard.shtml

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