Snort is vulnerable to a stack-based buffer overflow as a
result of DCE/RPC reassembly. This vulnerability is in a
dynamic-preprocessor enabled in the default configuration,
and the configuration for this preprocessor allows for
auto-recognition of SMB traffic to perform reassembly
on. No checks are performed to see if the traffic is part
of a valid TCP session, and multiple Write AndX requests
can be chained in the same TCP segment. As a result, an
attacker can exploit this overflow with a single TCP PDU
sent across a network monitored by Snort or Sourcefire.
Snort users who cannot upgrade immediately are advised to
disable the DCE/RPC preprocessor by removing the DCE/RPC
preprocessor directives from snort.conf and restarting
Snort. However, be advised that disabling the DCE/RPC
preprocessor reduces detection capabilities for attacks in
DCE/RPC traffic. After upgrading, customers should
re-enable the DCE/RPC preprocessor.