Ipswitch : Security Vulnerabilities, CVEs, Published In 1999 (Denial of service)

Buffer overflow in Ipswitch IMail Service 5.0 allows an attacker to cause a denial of service (crash) and possibly execute arbitrary commands via a long URL.

Buffer overflow in IMonitor in IMail 5.0 allows remote attackers to cause a denial of service, and possibly execute arbitrary commands, via a long string to port 8181.

WS_FTP server remote denial of service through cwd command.