Lpd over the Internet
Impact
This vulnerability allows remote users, or hackers, to write print jobs
to a printer queue via the Internet. Thus, unauthorized remote users can fill
the print queue and make the printer inaccessible to other users.
Background
The print process is controlled by a process called lpd.
The lpd process is a UNIX daemon that accepts print
requests from local and remote users.
The Problem
This vulnerability might allow hackers to write numerous print jobs to
a printer on the target system, and then pause the print process. By doing so,
the hacker denies print services to all users.
Resolution
The resolution to this vulnerability is to disable the lpd process,
which may be done by editing the inetd.conf file, commenting out the
lpd service, and by sending a HUP (a restart signal, usually sent to a process
after its configuration has changed), signal to the inetd
process.
If it is not feasible to disable the lpd
service, then you should at least limit access to the vulnerable
services to machines in your local network. This can be done by installing
TCP wrappers.