This Security Advisory describes multiple distinct vulnerabilities. These vulnerabilities are independent of each other.
Windows NT Domain Authentication Bypass Vulnerability
Because of a Microsoft Windows NT Domain authentication issue the Cisco ASA and Cisco PIX devices may be susceptible to a VPN authentication bypass vulnerability. Cisco ASA or Cisco PIX security appliances configured for IPSec or SSL-based remote access VPN may be vulnerable.
Note: Cisco ASA or Cisco PIX security appliances that are configured for IPSec or SSL-based remote access VPN using any other type of external authentication (that is, LDAP, RADIUS, TACACS+, SDI, or local database) are not affected by this vulnerability.
The Cisco ASA security appliance supports Microsoft Windows server operating systems that support NTLM version 1, collectively referred to as "NT servers". NT Domain authentication is supported only for remote access VPNs.
This vulnerability is documented in Cisco Bug ID CSCsu65735 ( registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) identifiers CVE-2008-3815.
IPv6 Denial of Service Vulnerability
A specially crafted IPv6 packet may cause the Cisco ASA and Cisco PIX security appliances to reload. Devices that are running software version 7.2(4)9 or 7.2(4)10 and configured for IPv6 may be vulnerable. This vulnerability does not affect devices that are configured only for IPv4.
Note: Devices that are running software versions in the 7.0, 7.1, 8.0, and 8.1 releases are not vulnerable.
To configure IPv6 on a Cisco ASA or Cisco PIX security appliance, at a minimum, each interface needs to be configured with an IPv6 link-local address. Additionally, you can add a global address to the interface.
Note: Only packets that are destined to the device (not transiting the device) may trigger the effects of this vulnerability. These packets must be destined to an interface configured for IPv6.
This vulnerability is documented in Cisco Bug ID CSCsu11575 ( registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) identifier CVE-2008-3816.
Crypto Accelerator Memory Leak Vulnerability
The Cisco ASA security appliances may experience a memory leak triggered by a series of packets. This memory leak occurs in the initialization code for the hardware crypto accelerator.
Note: Only packets destined to the device (not transiting the device) may trigger this vulnerability.
The following Cisco ASA features use the services the crypto accelerator provides, and therefore may be affected by this vulnerability:
- Clientless WebVPN, SSL VPN Client, and AnyConnect Connections
- ASDM (HTTPS) Management Sessions
- Cut-Through Proxy for Network Access
- TLS Proxy for Encrypted Voice Inspection
- IP Security (IPsec) Remote Access and Site-to-site VPNs
- Secure Shell (SSH) Access
This vulnerability is documented in Cisco Bug ID CSCsj25896 ( registered customers only) and has been assigned the Common Vulnerabilities and Exposures (CVE) identifier CVE-2008-3817.