The HTTP proxy in Symantec Gateway Security 5000 Series 2.0.1 and 3.0, and Enterprise Firewall 8.0, when NAT is being used, allows remote attackers to determine internal IP addresses by using malformed HTTP requests, as demonstrated using a get request without a space separating the URI.
secunia.com/advisories/20082
securityresponse.symantec.com/avcenter/security/Content/2006.05.10.html
securitytracker.com/id?1016057
securitytracker.com/id?1016058
www.securityfocus.com/archive/1/433876/30/5040/threaded
www.securityfocus.com/bid/17936
www.vupen.com/english/advisories/2006/1764
exchange.xforce.ibmcloud.com/vulnerabilities/26370