Software Engineering Institute

A buffer overflow vulnerability may be exploited during Notes authentication to a Lotus Domino server. Versions prior to 5.0.12 and 6.0 are affected. According to the Rapid7 Advisory:

Lotus Notes and Domino servers support a proprietary protocol called NotesRPC, commonly known as the Notes protocol. This protocol is usually bound to TCP port 1352, but can also use NetBIOS, Netware
SPX, Banyan Vines, and modem dialup for transport.

When a Notes client connects to a Notes server, it authenticates with the server to establish a session. This authentication consists of a series of exchanges in which the client and server present each other with challenges to verify each other's identity.

It is possible for an unauthenticated client to manipulate the data during this exchange to trigger a buffer overflow on the Notes server. This allows an attacker to overwrite large sections of the heap with arbitrary data. While our testing only covered TCP/IP, we believe it is possible for this overflow to be triggered via other protocols, including dialup. It is theoretically possible for an attacker to supply the data in such a way as to compromise the Notes server's security.

This vulnerability may be used by an unauthenticated attacker to cause a denial of service or potentially execute arbitrary code.

Lotus has published a support document for this issue. Upgrade to version 5.0.12 or 6.0 Gold or 6.0.1.