VULHUB ™

Telnetd is a commonly used remote-access server program for unix systems. The version of telnetd that ships with FreeBSD (likely other BSDs at least but uncomfirmed) contains a vulnerability that may allow a malicious remote attacker to cause a denial of service on the victim host. The TERMCAP telnet variable that is part of client-server negotiations can tell telnetd to search the filesystem for files containing termcap entries. A remote client can cause telnetd to search/read files anywhere on the filesystem via this variable, using I/O resources. Since this is performed before any authentication and telnetd is spawned by inetd, many telnetd processes could be started by an attacker each searching and reading files from the filesystem. This could theoretically result in an exhaustion of system resources. If exploited this might cause a denial of service on the victim host.

Telnetd is a commonly used remote-access server program for unix systems. The version of telnetd that ships with FreeBSD (likely other BSDs at least but uncomfirmed) contains a vulnerability that may allow a malicious remote attacker to cause a denial of service on the victim host. The TERMCAP telnet variable that is part of client-server negotiations can tell telnetd to search the filesystem for files containing termcap entries. A remote client can cause telnetd to search/read files anywhere on the filesystem via this variable, using I/O resources. Since this is performed before any authentication and telnetd is spawned by inetd, many telnetd processes could be started by an attacker each searching and reading files from the filesystem. This could theoretically result in an exhaustion of system resources. If exploited this might cause a denial of service on the victim host.