server/sv_main.c in Quake3 Arena, as used in ioquake3 before r1762, OpenArena, Tremulous, and other products, allows remote attackers to cause a denial of service (network traffic amplification) via a spoofed (1) getstatus or (2) rcon request.
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=665656
http://www.urbanterror.info/forums/topic/27825-drdos/
http://www.securityfocus.com/archive/1/522076
http://www.openwall.com/lists/oss-security/2012/03/26/5
http://www.ioquake.org/forums/viewtopic.php?f=12&t=1694
http://www.debian.org/security/2012/dsa-2442