Webwasher Denial of Service Vulnerability
Credit: The disclosure of this issue has been credited to National Australia
Bank Security
Assurance.
Vulnerable:
Secure Computing Webwasher 6.6.3 build 3102 and older versions running on
CGLinux 4/5, RHEL 4, Debian 4, SLES10
Not vulnerable:
Secure Computing Webwasher Builds 3150 and newer (all platforms)
Webwasher (all versions) for Windows
Webwasher (all versions) for Solaris
Webwasher (all versions) for some Linux (RHEL 3, SLES8, SLES9, Debian 3)
Webwasher 5.3 appliances (running CGLinux 3.x)
DISCUSSION
Due to a change in the behavior of newer Linux systems, we have become aware
that a Denial of Service attack can be launched against Webwasher running on
Linux based operating systems which will freeze the Webwasher service. If this
happens, Webwasher becomes unable to handle any request until the Webwasher
service is restarted.
The attack can be initiated by an internal user sending a specially crafted URL
to Webwasher. It could also be exploited by an external attacker by redirecting
proxy users to the exploit URL.
Who is affected?
Users of all Webwasher appliances version 6.x (CGLinux 4 or 5):
?If not running current version of Webwasher software but build numbers prior
to 3150
Users of Webwasher software versions
?If running on RedHat Enterprise Linux 4, Debian Linux 4 or Linux Suse Linue 10
?And if not running current version of Webwasher software but build numbers
prior to 3150
Who is not affected?
?All Webwasher installations on current versions ? build numbers 3150 or newer
?Webwasher Software customers on Windows, Solaris, Linux RedHat Enterprise 3,
Linux Suse 8 and 9, Debian 3.1 and Webwasher appliances running with CGLinux
3.x are not affected.
EXPLOIT
A special handcrafted URL has to be sent to Webwasher on the affected Linux
systems which will then freeze the application.
National Australia Bank Security Assurance has provided an undisclosed proof of
concept.
SOLUTION
The vendor has released Webwasher versions to address this:
?Webwasher 6.6.3 build 3150
?Webwasher 5.3.0 build 3159
Both are available at: https://extranet.webwasher.com/download/csm/index.html
Webwasher appliances can be upgraded automatically via the GUI