ISC DHCPD contains format string vulnerability when logging DNS-update requests

2002-05-08T00:00:00
ID VU:854315
Type cert
Reporter CERT
Modified 2003-01-13T00:00:00

Description

Overview

The DHCP daemon (DHCPD) is a server that is used to allocate network addresses and assign configuration parameters to dynamically configured hosts. A format string vulnerability may permit an intruder to execute code with the privileges of the DHCP daemon (typically root).

Description

The Internet Software Consortium (ISC) produces a DHCP server. DHCPD listens for requests from client machines connecting to the network. Versions 3 to 3.0.1rc8 inclusive of DHCPD contain an option (NSUPDATE) that is compiled in by default. NSUPDATE allows the DHCP server to send an update to the DNS server after processing a DHCP request. The DNS server responds by sending a message back to the DHCP server. The response from the DNS server can contain user-supplied data. When this message is received, the DHCP server logs the transaction. A format string vulnerability exists in the DHCPD code that logs the transaction. This vulnerability may permit an attacker to execute code with the privileges of the DHCP daemon.


Impact

A remote attacker can execute arbitrary code on the vulnerable host with the privileges of the DHCP server (DHCPD), typically root.


Solution

Obtain a patch from vendor.


If you cannot upgrade, apply the following patch.

--- common/print.c Tue Apr 9 13:41:17 2002
+++ common/print.c.patched Tue Apr 9 13:41:56 2002
@@ -1366,8 +1366,8 @@
s++ = '.';
s++ = 0;
if (errorp)
- log_error (obuf);
+ log_error ("%s",obuf);
else
- log_info (obuf);
+ log_info ("%s",obuf);
}

endif / NSUPDATE /**


Systems Affected

Vendor| Status| Date Notified| Date Updated
---|---|---|---
Alcatel| | 07 May 2002| 29 May 2002
Conectiva| | -| 13 May 2002
FreeBSD| | 06 May 2002| 07 May 2002
ISC| | -| 08 May 2002
NetBSD| | 06 May 2002| 08 May 2002
Apple Computer Inc.| | 06 May 2002| 14 May 2002
Cray Inc.| | 06 May 2002| 13 May 2002
F5 Networks| | 07 May 2002| 08 May 2002
Fujitsu Limited| | 06 May 2002| 14 May 2002
Hewlett-Packard Company| | 06 May 2002| 08 May 2002
IBM| | 06 May 2002| 07 May 2002
Lotus Development Corporation| | 07 May 2002| 08 May 2002
Microsoft Corporation| | 07 May 2002| 08 May 2002
NEC Corporation| | 06 May 2002| 14 May 2002
Nortel Networks| | 07 May 2002| 09 May 2002
If you are a vendor and your product is affected, let us know.

CVSS Metrics

Group | Score | Vector
---|---|---
Base | N/A | N/A
Temporal | N/A | N/A
Environmental | N/A | N/A

References

  • <http://www.ngsec.com/docs/advisories/NGSEC-2002-2.txt>
  • <http://www.isc.org/products/DHCP/>
  • <http://www.securityfocus.com/bid/4701>

Credit

The CERT Coordination Center acknowledges Next Generation Security Technologies as the discoverer of this vulnerability and thanks them and The Internet Software Consortium (ISC) for their cooperation, reporting and analysis of this vulnerability.

This document was written by Ian A. Finlay.

Other Information

  • CVE IDs: CAN-2002-0702
  • CERT Advisory: CA-2002-12
  • Date Public: 08 May 2002
  • Date First Published: 08 May 2002
  • Date Last Updated: 13 Jan 2003
  • Severity Metric: 46.17
  • Document Revision: 47