CVE-2018-6855: Buffer Overflow

Sophos SafeGuard Enterprise before 8.00.5, SafeGuard Easy before 7.00.3, and SafeGuard LAN Crypt before 3.95.2 are vulnerable to Local Privilege Escalation via IOCTL 0x80202014. By crafting an input buffer we can control the execution path to the point where the constant 0xFFFFFFF will be written to a user-controlled address. We can take advantage of this condition to modify the SEPTOKENPRIVILEGES structure of the Token object belonging to the exploit process and grant SEDEBUGNAME privilege. This allows the exploit process to interact with higher privileged processes running as SYSTEM and execute code in their security context.