CVE Catalog

CVE-2005-4437

High
Published: Translated: NVD NIST

Summary

The vulnerability in MD5 Neighbor Authentication in EIGRP (Cisco IOS 11.3 and later) does not include the Message Authentication Code (MAC) in the checksum. This allows an attacker to sniff message hashes and replay HELLO packets or cause a denial of service by sending spoofed neighbor announcements, resulting in an ARP storm on the local network.

Risk Assessment

The organization faces the risk of EIGRP session hijacking and network disruption via a DoS attack that can overwhelm the local network with ARP traffic.

Recommendation

It is recommended to upgrade IOS to a version that fixes MD5 authentication in EIGRP or to use alternative authentication mechanisms such as HMAC-SHA-256.

Related vulnerabilities

Original NVD description (English source)

MD5 Neighbor Authentication in Extended Interior Gateway Routing Protocol (EIGRP) 1.2, as implemented in Cisco IOS 11.3 and later, does not include the Message Authentication Code (MAC) in the checksum, which allows remote attackers to sniff message hashes and (1) replay EIGRP HELLO messages or (2) cause a denial of service by sending a large number of spoofed EIGRP neighbor announcements, which results in an ARP storm on the local network.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS