Stack-based buffer overflow in Active Directory in Windows 2000 before SP4 allows remote attackers to cause a denial of service (reboot) and possibly execute arbitrary code via an LDAP version 3 search request with a large number of (1) "AND," (2) "OR," and possibly other statements, which causes LSASS.EXE to crash.
http://www.securityfocus.com/bid/7930
http://www.kb.cert.org/vuls/id/594108
http://support.microsoft.com/default.aspx?kbid=319709