Luigi Auriemma has discovered some vulnerabilities in WinCom LPD Total, which can be exploited by malicious people to bypass certain security restrictions, cause a DoS (Denial of Service), or compromise a vulnerable system.

1) A boundary error in the Line Printer Daemon (LPDService.exe) when processing print jobs with an overly long control file name can be exploited to cause a buffer overflow by sending a specially crafted print job to default port 515/TCP.

Successful exploitation may allow execution of arbitrary code, but requires knowledge of an existing printer queue name.

2) Two boundary errors in the Line Printer Daemon can be exploited to cause stack-based buffer overflows by sending specially crafted packets to default port 13500/TCP.

Successful exploitation allows execution of arbitrary code.

3) Missing authentication checks in the Line Printer Daemon can be exploited to perform certain actions on the service such as e.g. adding a printer queue, which can be used to aid in exploiting vulnerability #1.

The vulnerabilities are confirmed in version 3.0.2.623. Other versions may also be affected.

Solution
Restrict network access to the Line Printer Daemon service.

Provided and/or discovered by
Luigi Auriemma

Changelog
Further details available to Secunia VIM customers

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

Deep Links
Links available to Secunia VIM customers