SID 1:3626

Rule Category

PROTOCOL-ICMP -- Snort alerted on Internet Control Message Protocol (ICMP) traffic, which allows hosts to send error messages about interruptions in traffic. Administrators can use ICMP to perform diagnostics and troubleshooting, but the protocol can also be used by attackers to gain information on a network. This protocol is vulnerable to several attacks, and many administrators block it altogether, or block selective messages.

Alert Message

PROTOCOL-ICMP PATH MTU denial of service attempt

Rule Explanation

Multiple TCP/IP and ICMP implementations, when using Path MTU (PMTU) discovery (PMTUD), allow remote attackers to cause a denial of service (network throughput reduction for TCP connections) via forged ICMP ("Fragmentation Needed and Don't Fragment was Set") packets with a low next-hop MTU value, aka the "Path MTU discovery attack." NOTE: CVE-2004-0790, CVE-2004-0791, and CVE-2004-1060 have been SPLIT based on different attacks; CVE-2005-0065, CVE-2005-0066, CVE-2005-0067, and CVE-2005-0068 are related identifiers that are SPLIT based on the underlying vulnerability. While CVE normally SPLITs based on vulnerability, the attack-based identifiers exist due to the variety and number of affected implementations and solutions that address the attacks instead of the underlying vulnerabilities. Impact: CVSS base score 5.0 CVSS impact score 2.9 CVSS exploitability score 10.0 confidentialityImpact NONE integrityImpact NONE availabilityImpact NONE Details: Ease of Attack:

What To Look For

No information provided

Known Usage

No public information

False Positives

No known false positives

Contributors

Talos research team. This document was generated from data supplied by the national vulnerability database, a product of the national institute of standards and technology. For more information see [nvd].