NTP: Remote execution of arbitrary code

Security Team Contact Address

Updated May 26, 2009

1. Gentoo Linux Security Advisory

Advisory Reference	GLSA 200905-08 / ntp
Release Date	May 26, 2009
Latest Revision	May 26, 2009: 01
Impact	high
Exploitable	remote

Package	Vulnerable versions	Unaffected versions	Architecture(s)
net-misc/ntp	< 4.2.4_p7	>= 4.2.4_p7	All supported architectures

Related bugreports: #263033, #268962

Synopsis

Multiple errors in the NTP client and server programs might allow for the remote execution of arbitrary code.

2. Impact Information

Background

NTP contains the client and daemon implementations for the Network Time Protocol.

Description

Multiple vulnerabilities have been found in the programs included in the NTP package:

Apple Product Security reported a boundary error in the cookedprint() function in ntpq/ntpq.c, possibly leading to a stack-based buffer overflow (CVE-2009-0159).
Chris Ries of CMU reported a boundary error within the crypto_recv() function in ntpd/ntp_crypto.c, possibly leading to a stack-based buffer overflow (CVE-2009-1252).

Impact

A remote attacker might send a specially crafted package to a machine running ntpd, possibly resulting in the remote execution of arbitrary code with the privileges of the user running the daemon, or a Denial of Service. NOTE: Successful exploitation requires the "autokey" feature to be enabled. This feature is only available if NTP was built with the 'ssl' USE flag.

Furthermore, a remote attacker could entice a user into connecting to a malicious server using ntpq, possibly resulting in the remote execution of arbitrary code with the privileges of the user running the application, or a Denial of Service.

3. Resolution Information

Workaround

You can protect against CVE-2009-1252 by disabling the 'ssl' USE flag and recompiling NTP.

Resolution

All NTP users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=net-misc/ntp-4.2.4_p7"

4. References