Title: Cisco VPN Client for Windows Local Denial of Service Vulnerability
Severity: LOW
Description:
Cisco VPN Client is a freely available IPsec client application that is used to connect to Cisco VPN servers. It is available for multiple platforms, including Microsoft Windows, Apple Mac OS X, UNIX, and Linux.
Cisco VPN Client for Windows is prone to a local denial-of-service vulnerability because the software's IPsec driver fails to handle certain IOCTLs.
Specifically, when the IOCTL 0x80002038 is executed with an argument smaller than 39 bytes on the '\\.\CVPNDRVA' device, kernel memory will become corrupted. This occurs because the memory buffer passed to the IOCTL is smaller than expected, causing uninitialized memory to be copied and used by the driver. Further operations on the corrupted memory in the kernel will cause the computer to crash.
Successfully exploiting this issue allows local attackers to crash affected computers, denying further service to legitimate users.
This issue affects 'cvpndrva.sys' 5.0.02.0090; other versions of the driver may also be affected.
Affected Products:
- Cisco VPN Client for Windows 5.0.02.0090
References:
- Cisco Systems: VPN Client
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