Character Generator Protocol: Difference between revisions

Revision as of 13:01, 12 May 2025

Revision as of 23:28, 16 June 2025

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==Abuse==

The service was used maliciously to crash [[Microsoft]] [[Name server|___domain name servers]] (DNS) running [[Windows NT 4.0]] by piping the arbitrary characters straight into the DNS server listening port (<code>telnet ntbox 19 | telnet ntbox 53</code>).<ref>{{cite web|url=http://support.microsoft.com/kb/169461|title=Access Violation in Dns.exe Caused by Malicious Telnet Attack|date=2006-11-01|publisher=Support.microsoft.com|archive-url=https://web.archive.org/web/20140819172557/http://support.microsoft.com/kb/169461|url-status=live|accessdate=2009-05-31|archive-date=2014-08-19}}</ref><ref>{{Cite news|url=httphttps://www.itprotoday.com/security/ms-dns-server-subject-denial-service-attack|title=MS DNS Server subject to Denial of Service Attack|date=1997-05-27|work=IT Pro|access-date=2018-02-05}}</ref> However, the attack may have been a symptom of improper buffer management on the part of Microsoft's DNS service and not directly related to the CHARGEN service.{{Citation needed|date=August 2010}}

UDP CHARGEN is commonly used in denial-of-service attacks. By using a fake source address the attacker can send bounce traffic off a UDP CHARGEN application to the victim. UDP CHARGEN sends 200 to 1,000 times more data than it receives, depending upon the implementation. This "traffic multiplication" is also attractive to an attacker because it obscures the attacker's IP address from the victim.{{Citation needed|date=April 2024}}