libs/comverp.c in Courier MTA before 0.53.2 allows attackers to cause a denial of service (CPU consumption) via unknown vectors involving usernames that contain the "=" (equals) character, which is not properly handled during encoding.

A Denial of Service vulnerability has been found in the function for encoding email addresses. Addresses containing a '=' before the '@' character caused the Courier to hang in an endless loop, rendering the service unusable.

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

A bug has been discovered in the Courier Mail Server that can result in a number of processes to consume arbitrary amounts of CPU power.

The remote host is affected by the vulnerability described in GLSA-200608-06 (Courier MTA: Denial of Service vulnerability)

    Courier MTA has fixed a security issue relating to usernames containing     the '=' character, causing high CPU utilization.
  Impact :

    An attacker could exploit this vulnerability by sending a specially     crafted email to a mail gateway running a vulnerable version of Courier     MTA.
  Workaround :

    There is no known workaround at this time.

The remote host is running Courier Mail Server, an open source mail server for Linux and Unix.  The installed version of Courier is prone to a flaw in the way that it handles malformed 'login' strings.  Specifically, an attacker who sends a username that includes a '

ID	Name	Product	Family	Severity
27866	Ubuntu 5.04 / 5.10 / 6.06 LTS : courier vulnerability (USN-294-1)	Nessus	Ubuntu Local Security Checks	high
22643	Debian DSA-1101-1 : courier - programming error	Nessus	Debian Local Security Checks	high
22148	GLSA-200608-06 : Courier MTA: Denial of Service vulnerability	Nessus	Gentoo Local Security Checks	high
3646	Courier Mail Server < 0.53.2 Crafted Username Encoding DoS	Nessus Network Monitor	SMTP Servers	high

Detections

Analytics

CVE-2006-2659

high

Tenable Plugins

high

high

high

high