PCNetSoftware RAC Server Denial Of Service(Disabled Keyboard Or Crash) Vulnerability
1 Apr. 2016
PCNetSoftware RAC Server 4.0.4 and 4.0.5 allows local users to cause a denial of service (disabled keyboard or crash) via a large input buffer to unspecified IOCTL requests in RACDriver.sys, which triggers a buffer over-read.
The information has been provided by Kyriakos Economou.
* PCNetSoftware RAC Server till 4.0.5
* PCNetSoftware RAC Server 4.0.6 and later
Latest and possibly earlier versions of RAC Server software are vulnerable to local DoS attacks that can cause either to disable the keyboard input or to kill the system through a BSoD, by sending specific IOCTL codes to RACDriver.sys kernel mode driver. The attacker can choose between the two. The BSoD is triggered because the size of the input buffer received by the driver is not correctly validated against the size of a static buffer, inside the driver module itself, from where the driver transfers some data to the allocated buffer. The vulnerable function assumes that the size of the input buffer will always be less or equal to the static one. This leads to memory access violation inside the kernel address space when the input buffer is too big, because the vulnerable function will attempt to read outside the module itself.