Luigi Auriemma has discovered two vulnerabilities in Larson Network Print Server, which can be exploited by malicious people to cause a DoS (Denial of Service) or compromise a vulnerable system.

1) A boundary error in the LST Network Print Server service (NPSpcSVR.exe) when handling the "LICENSE" command can be exploited to cause a stack-based buffer overflow via a "LICENSE" command with an overly long license string sent to default port 3114/TCP.

Successful exploitation allows execution of arbitrary code.

2) A format string error in the in the LST Network Print Server service when handling e.g. the "USEP" command can be exploited via command arguments containing format string specifiers.

Successful exploitation may allow execution of arbitrary code.

The vulnerabilities are confirmed in version 9.4.2 build 105. Other versions may also be affected.

Solution
Restrict network access to the service.

Provided and/or discovered by
Luigi Auriemma

Changelog
Further details available to Secunia VIM customers

Original Advisory
http://aluigi.altervista.org/adv/lstnpsx-adv.txt

Deep Links
Links available to Secunia VIM customers