Red Hat Bugzilla – Bug 90463
nscd uses cached reverse lookups for later forward lookups
Last modified: 2007-04-18 12:53:34 EDT
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User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.3) Gecko/20030314
Description of problem:
nscd uses the result of GETHOSTBYADDR requests to answer later GETHOSTBYNAME
An attacker might poison the nscd cache and redirect IP traffic.
See the attachments for a sample session and configuration files.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. setup nameserver with a PTR RR resolving to "localhost."
2. connect to the victim host using the IP of the PTR RR
3. now the victim's nscd cache is poinsoned and traffic to the hostname
localhost will we directed to the attacher's IP
Created attachment 91562 [details]
Example session 1
Created attachment 91563 [details]
Example session 2
Created attachment 91564 [details]
nscd configuration file
Created attachment 91565 [details]
Created attachment 91566 [details]
This shouldn't be a problem anymore in RHL9. Please try it.
Verified -- RHL9 (all updates installed) does not exhibit this problem.