All versions of ProxySG prior to 6.1.2 are vulnerable.

ProxySG 6.1 - a fix is available in SGOS 6.1.2.1.
ProxySG 5.5 - a fix is available in SGOS 5.5.4.1
ProxySG 5.4 - a fix is available in SGOS 5.4.5.1.
ProxySG 5.3 - please upgrade to a later version.
ProxySG 4.3 - an interim fix is available in SGOS 4.3.4.2 patch release.

For information on how to upgrade SGOS, please see KB3608.

Malicious scripts are commonly encoded in web pages and run without a user's knowledge.  ProxySG can be configured to supplement virus scanning of Web content by detecting and removing the HTML tags that launch active content such as Java applets or scripts.  In addition, the removed content can be replaced with predefined material, also called active content transformation.

ProxySG can detect three types of JavaScript active content:

1. Anything within the <script></script> tags.
2. JavaScript events within HTML attributes with onEventName names (e.g., onClick, onLoad).
3. JavaScript within HTML attribute values using the javascript: URI scheme.

Vulnerable SGOS versions only detect these tags and attributes encoded in ASCII.  Tags and attributes encoded in other formats will elude detection.

SGOS has been fixed to provide better detection of JavaScript active content within an HTML document.  SGOS will now detect tags and attributes encoded using hex and UTF-8 entities, and when formatting characters such as newlines and tabs are used.  This update will allow ProxySG to remove or replace more instances of JavaScript that had previously not been detected.

CVSS v2 base score: 5.0 (AV:N/AC:L/Au:N/C:N/I:P/A:N)

Malicious active content is difficult to distinguish from legitimate active content. ProxySG active content transformation and removal is designed to supplement WebPulse, virus scanners, and browser protections that detect and prevent malicious active content. Customers are encouraged to employ multiple layers of protection to achieve the best results.