[Full-disclosure] Lotus Sametime User Enumeration Vulnerability - Security Advisory - SOS-09-004

Lotus Sametime User Enumeration Vulnerability - Security Advisory -
SOS-09-004

Release Date. 9-Jul-2009

Vendor Notification Date. 2-Jun-2009

Product. IBM Lotus Instant Messaging and Web Conferencing (Sametime)

Platform. Windows (verified), possibly others

Affected versions. IBM Lotus Instant Messaging and Web Conferencing
(Sametime) 6.5.1 (verified), possibly others

Severity Rating. Low

Impact. Exposure of sensitive information

Attack Vector. Remote without authentication

Solution Status. Vendor patch not yet available

CVE reference. Not yet allocated

Details.

IBM Lotus Sametime is an enterprise instant messaging and web conferencing
application. During an application penetration test Sense of Security
identified a user enumeration vulnerability when trying to connect to the
Sametime server using the Sametime Connect Client. This occurred as a result
of varying response times depending on whether or not a valid user name is
supplied.

The client takes significantly longer to display the 'Invalid logon' error
message when a valid username (and invalid password) is provided (5-8
seconds). This is a result of additional information exchanges occurring
between the server and client.

When an invalid username (and password) is supplied, the error is displayed
almost instantaneously (1-3 seconds).

This can be used to enumerate valid user names.

Solution.

The vendor has advised that IBM is looking to eliminate this behaviour
completely in a future release.

Discovered by.

Karan Khosla from SOS Labs.

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The latest version of this advisory can be found at:

http://www.senseofsecurity.com.au/advisories/SOS-09-004.pdf

Other Sense of Security advisories can be found at:

http://www.senseofsecurity.com.au/research/it-security-advisories.php