Zero-Day Advisory

Fortinet Discovers Microsoft Windows LPD Service Remote DoS Vulnerability


Fortinet's FortiGuard Labs has discovered a remote DoS vulnerability in Microsoft Windows Line Printer Daemon (LPD) service.

The LPD service enables client computers to send print requests to the LPD service on the server using the Line Printer Remote (LPR) protocol. More information about the Line Printer Remote protocol can be found at

Windows LPD service is susceptible to a remote DoS vulnerability. The issue occurs when the LPD service does not properly deal with a specially crafted network packet. A remote attacker may be able to exploit this to stop Windows LPD service.


FortiGuard Labs released the following FortiGate IPS signature which covers this specific vulnerability:

Released Dec 05, 2016

Users should apply the solution provided by Microsoft.


Fortinet reported the vulnerability to Microsoft on November 1, 2016.

Microsoft told Fortinet "The issue was fixed in Windows Redstone 2." on May 17, 2018.


This vulnerability was discovered by Honggang Ren of Fortinet's FortiGuard Labs.

IPS Subscription

Fortinet customers who subscribe to Fortinet's intrusion prevention (IPS) service should be protected against this vulnerability with the appropriate configuration parameters in place. Fortinet's IPS service is one component of FortiGuard Subscription Services, which also offer comprehensive solutions such as antivirus, Web content filtering and antispam capabilities. These services enable protection against threats on both application and network layers. FortiGuard Services are continuously updated by FortiGuard Labs, which enables Fortinet to deliver a combination of multi-layered security intelligence and true zero-day protection from new and emerging threats. These updates are delivered to all FortiGate, FortiMail and FortiClient products. Fortinet strictly follows responsible disclosure guidelines to ensure optimum protection during a threat's lifecycle.