Ubuntu 4.10 : netkit-telnet vulnerabilities (USN-101-1)
High Nessus Plugin ID 20487
SynopsisThe remote Ubuntu host is missing one or more security-related patches.
DescriptionA buffer overflow was discovered in the telnet client's handling of the LINEMODE suboptions. By sending a specially constructed reply containing a large number of SLC (Set Local Character) commands, a remote attacker (i. e. a malicious telnet server) could execute arbitrary commands with the privileges of the user running the telnet client. (CAN-2005-0469)
Michal Zalewski discovered a Denial of Service vulnerability in the telnet server (telnetd). A remote attacker could cause the telnetd process to free an invalid pointer, which caused the server process to crash, leading to a denial of service (inetd will disable the service if telnetd crashed repeatedly), or possibly the execution of arbitrary code with the privileges of the telnetd process (by default, the 'telnetd' user). Please note that the telnet server is not officially supported by Ubuntu, it is in the 'universe' component.
Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
SolutionUpdate the affected telnet and / or telnetd packages.