Editing Denial-of-service attack (section)

===Teardrop attacks===
{{see also|IP fragmentation attack}}

A '''teardrop attack''' involves sending [[Mangled packet|mangled]] [[IP fragment]]s with overlapping, oversized payloads to the target machine. This can crash various operating systems because of a bug in their [[TCP/IP]] [[IPv4#Fragmentation and reassembly|fragmentation re-assembly]] code.<ref name="CERT-1">{{cite web |year=1998 |title=CERT Advisory CA-1997-28 IP Denial-of-Service Attacks |url=https://vuls.cert.org/confluence/display/historical/CERT+Advisory+CA-1997-28+IP+Denial-of-Service+Attacks |access-date=July 18, 2014 |publisher=CERT}}</ref> [[Windows 3.1x]], [[Windows 95]] and [[Windows NT]] operating systems, as well as versions of [[Linux]] prior to versions 2.0.32 and 2.1.63 are vulnerable to this attack.{{efn|Although in September 2009, a vulnerability in [[Windows Vista]] was referred to as a ''teardrop attack'', this targeted [[Server Message Block|SMB2]] which is a higher layer than the TCP packets that teardrop used).<ref>{{cite news|url=http://www.zdnet.com/blog/security/windows-7-vista-exposed-to-teardrop-attack/4222 |archive-url=https://web.archive.org/web/20101106101436/http://www.zdnet.com/blog/security/windows-7-vista-exposed-to-teardrop-attack/4222 |url-status=dead |archive-date=6 November 2010 |title=Windows 7, Vista exposed to 'teardrop attack' |work=ZDNet |date=September 8, 2009 |access-date=2013-12-11}}</ref><ref>{{cite web|url=http://www.microsoft.com/technet/security/advisory/975497.mspx |title=Microsoft Security Advisory (975497): Vulnerabilities in SMB Could Allow Remote Code Execution |publisher=Microsoft.com |date=September 8, 2009 |access-date=2011-12-02}}</ref>}} One of the fields in an [[IP header]] is the ''fragment offset'' field, indicating the starting position, or offset, of the data contained in a fragmented packet relative to the data in the original packet. If the sum of the offset and size of one fragmented packet differs from that of the next fragmented packet, the packets overlap. When this happens, a server vulnerable to teardrop attacks is unable to reassemble the packets resulting in a denial-of-service condition.<ref>{{Citation |last=Bhardwaj |first=Akashdeep |title=Solutions for DDoS Attacks on Cloud Environment |date=2023-06-12 |work=New Age Cyber Threat Mitigation for Cloud Computing Networks |pages=42–55 |url=http://dx.doi.org/10.2174/9789815136111123010006 |access-date=2024-02-09 |publisher=BENTHAM SCIENCE PUBLISHERS |doi=10.2174/9789815136111123010006 |isbn=978-981-5136-11-1}}</ref>