Fragmentation is a technique used by attackers to evade detection by Intrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS). By breaking down packets into smaller fragments, attackers can make it more difficult for these security systems to detect malicious payloads or signature-based patterns associated with known attacks. This method exploits the fact that some IDS/IPS solutions may not properly reassemble packet fragments for analysis, thereby allowing malicious fragments to pass through undetected.
References:In its coverage of network security mechanisms and evasion techniques, the ECIH v3 certification details how attackers exploit vulnerabilities in the implementation of IDS and IPS systems, including the use of packet fragmentation.