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LPRng Print Queue Control Vulnerability

Solution:
In a post to BugTraq, the maintainer of LPRng, Patrick Powell, presented a temporary fix by enabling the security features. This configuration fix makes LPRng check source ports and will be setup by default upon next release. The author did stress that this was not a complete fix and that the problem lied in the protocol.

# check originating ports on connections
REJECT SERVICE=X NOT PORT=721-731

Add the above line to /etc/lpd.conf.