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ypxfrd daemon fails to properly validate user supplied arguments in "getdbm" procedure

Vulnerability Note VU#538033

Original Release Date: 2002-10-10 | Last Revised: 2003-04-09

Overview

A vulnerability in the ypxfrd daemon may allow a local attacker to read arbitrary files on the vulnerable system.

Description

Janusz Niewiadomski, of iSEC, discovered this vulnerability and produced the following advisory.

Issue:
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Improper arguments validation in ypxfrd may allow local attacker to read any file on the system.

Description:
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ypxfrd daemon is used for speed up the distribution of large NIS maps from NIS master to NIS slave servers.

Details:
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When getdbm procedure is called, ypxfrd daemon creates a path to the /var/yp/domain/map file (where domain and map are arguments provided in the request). Unfortunately it fails to check if both arguments contains slash or dot characters, thus making databases outside /var/yp directory accessible. A symlink done can override .pag / .dir file extension limitation, allowing local attacker to read any file on the system.

Impact:
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When ypxfrd is configured and running, local attacker is able to read any file on the system. It is also possible to remotely read database outside /var/yp directory, depending on the securenets configuration.

Impact

A local attacker my be able to read any file on the vulnerable system. This may lead to privilege escalation.

Solution

Apply a patch.

Vendor Information

538033
 

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CVSS Metrics

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References

Acknowledgements

Thanks to Janusz Niewiadomski for reporting this vulnerability. We also thank Sun Microsystems for their assistance.

This document was written by Ian A Finlay.

Other Information

CVE IDs: CVE-2002-1199
Severity Metric: 4.50
Date Public: 2002-10-09
Date First Published: 2002-10-10
Date Last Updated: 2003-04-09 19:31 UTC
Document Revision: 7

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