tcpdump vulnerable to buffer overflow via parsing of AFS ACL packets

Overview

Tcpdump version 3.5 contains a buffer overflow vulnerability permitting unauthorized remote root access.

Description

Tcpdump version 3.5 added support for handling AFS packets. Unfortunately the code responsible for printing AFS access control lists contains an unchecked buffer that can be overflowed by a remote attacker by sending a crafted AFS packet into the target network. Any machine on the target network that is running tcpdump with a large (> ~500) snaplen argument when the hostile packet arrives can be made to execute arbitrary code. Since tcpdump requires root privileges in order to run, the arbitrary code will also run with root privileges. Fixed in version 3.6.1.

Note that a program that successfully exploits this vulnerability was publicly released on the BugTraq mailing list on January 11, 2001.

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Impact

Attackers can remotely execute arbitrary code with root privileges on a vulnerable host.

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Solution

Upgrade to version 3.6.1 or greater.

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Filter incoming dst UDP 7000 packets from untrusted networks. Exclude dst UDP 7000 packets from tcpdump capture, e.g. “tcpdump not udp dst port 7000”.

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Vendor Information

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FreeBSD.org __ Affected

Updated: June 21, 2001

Status

Affected

Vendor Statement

See <ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-00:61,tcpdump.v1.1.asc&gt;

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Addendum

The CERT/CC has no additional comments at this time.

If you have feedback, comments, or additional information about this vulnerability, please send us [email](<mailto:[email protected]?Subject=VU%23776781 Feedback>).

MandrakeSoft __ Affected

Updated: June 21, 2001

Status

Affected

Vendor Statement

See <http://www.linux-mandrake.com/en/security/2001/MDKSA-2001-056.php3?dis=7.2&gt;

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Addendum

The CERT/CC has no additional comments at this time.

If you have feedback, comments, or additional information about this vulnerability, please send us [email](<mailto:[email protected]?Subject=VU%23776781 Feedback>).

CVSS Metrics

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References

• <http://www.securityfocus.com/bid/1870&gt;
• http://www.securityfocus.com/templates/archive.pike?list=1&mid=155883

Acknowledgements

First public disclosure by [email protected] and the !Hispahack Research Team.

Other Information

CVE IDs:	CVE-2000-1026
Severity Metric:	16.03 Date Public: