Cisco announced two new security updates this evening.

Crypto Library

A vulnerability (CVE-2006-3894) in a third-party cryptography library used in some Cisco products could lead to a sustained DoS attack. Although an attacker may be able to send a malformed ASN.1 packet and cause the affected device to crash, it is not believed that this vulnerability can allow a device to be compromised. A list of affected products and associated Cisco bug IDs is included in Table 1 below. More detailed information may be found on Cisco’s web site.

Table 1. Crypto Library Vulnerabilities
CSCsd85587 Cisco IOS
CSCsg41084 Cisco IOS XR
CSCse91999 Cisco PIX and ASA Security Appliances
CSCsi97695 Cisco Firewall Service Module (FWSM)
CSCsg44348 Cisco Unified CallManager

IOS SSL

A device running Cisco IOS may crash if an attacker sends malformed SSL packets during the protocol exchange. An attacker may take advantage of these vulnerabilities to initiate a DoS attack. A list of Cisco bug IDs and affected packet types is included in Table 2 below. The following applications in Cisco IOS use SSL and are vulnerable to these attacks:

  • Hyper Text Transfer Protocol over SSL (HTTPS).
  • Cisco Network Security (CNS) Agent with SSL support
  • Firewall Support of HTTPS Authentication Proxy
  • Cisco IOS Clientless SSL VPN (WebVPN) support

Further information may be found on Cisco’s web site.

Table 2. Cisco IOS SSL Vulnerabilities
CSCsb12598 ClientHello messages
CSCsb40304 ChangeCipherSpec messages
CSCsd92405 Finished messages
| More

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