Trend Micro InterScan VirusWall for Windows NT 3.52 does not record the sender's IP address in the headers for a mail message when it is passed from VirusWall to the MTA, which allows remote attackers to hide the origin of the message.
Exploitability
AV:NAC:LAu:NImpact
C:NI:PA:N5/AV:N/AC:L/Au:N/C:N/I:P/A:N