Exposure of Sensitive Information to an Unauthorized Actor
The default configuration of SGOS in Blue Coat ProxySG before 22.214.171.124, 6.5 before 126.96.36.199, and 6.6 before 188.8.131.52 forwards authentication challenges from upstream origin content servers (OCS) when used in an explicit proxy deployment, which makes it easier for remote attackers to obtain sensitive information via a 407 (aka Proxy Authentication Required) HTTP status code, as demonstrated when using NTLM authentication.
CWE-200 - Information Exposure
An information exposure vulnerability is categorized as an information flow (IF) weakness, which can potentially allow unauthorized access to otherwise classified information in the application, such as confidential personal information (demographics, financials, health records, etc.), business secrets, and the application's internal environment.