Qmail email RCPT denial of service
| qmail-rcpt (208) |  Low Risk |
Description:
The qmail server is vulnerable to a denial of service attack. By configuring the `Threshold¿ advanced parameter, an attacker can adjust the number of RCPTs that are legitimately allowed in a session. The default value for this parameter is 65535. An attacker can send an RCPT command with an extremely large number of recipients to the Qmail server to consume all memory resources on the server and crash the server.
Platforms Affected:
- Compaq, Tru64
- Dan Bernstein, qmail 1.01
- Data General, DG/UX
- HP, HP-UX
- IBM, AIX
- Linux, Kernel
- SCO, SCO Unix
- SGI, IRIX
- Sun, Solaris
- WindRiver, BSDOS
Remedy:
Upgrade to the latest version of qmail (1.03 or later), available from the qmail Web site. See References.
Consequences:
Denial of Service
References:
- BugTraq Mailing List, 1997-06-12 7:04:01, Re: Denial of service (qmail-smtpd) at http://marc.theaimsgroup.com/?l=bugtraq&m=87602558319029&w=2.
- D. J. Bernstein's Web site, Wietse Venema's slander at http://cr.yp.to/qmail/venema.html.
- Qmail Mailing List, qmail-dos-2.c, another denial of service attack at http://www.ornl.gov/its/archives/mailing-lists/qmail/1997/06/msg00322.html.
- Qmail Web site, qmail: a replacement for sendmail at http://www.qmail.org/top.html.
- BID-2237: QMail RCPT Denial of Service Vulnerability
- CVE-1999-0144: Denial of service in Qmail by specifying a large number of recipients with the RCPT command.
Reported:
Jun 11, 1997
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