oss-sec mailing list archives
Re: CVE Request -- dhcp: DoS (excessive CPU use) by opening an OMAPI connection
From: Jan Lieskovsky <jlieskov () redhat com>
Date: Wed, 06 Apr 2011 20:18:12 +0200
Jan Lieskovsky wrote:
Hello Josh, Steve, vendors,A security flaw was found in the way DHCP (Dynamic Host Configuration Protocol) server processed remote connections when the dhcpd was configured to provide Object Management API (OMAPI) capability. A remote attacker could use this flaw to cause denial of service (excessive CPU use and dhcpd daemon unreachability).References: [1] https://bugzilla.novell.com/show_bug.cgi?id=680298 [2] https://lists.isc.org/pipermail/dhcp-users/2011-February/012780.html [3] https://lists.isc.org/pipermail/dhcp-users/2011-February/012781.html [4] https://bugzilla.redhat.com/show_bug.cgi?id=666441 [5] http://www.mentby.com/Group/dhcp-users/omapi-not-working-in-420.htmlNote: Though looks as minor / low severity issue, under proper configuration looks to be a way, how to get dhcpd completely unresponsive for furtherrequests. Could you allocate a CVE id for this? (though opened for discussion if this being more to be a bug, than a real security issue).
The dhcpd(8) manual page: [6] http://linux.die.net/man/8/dhcpd suggests it's possible to "The control object allows you to shut the server down." [the Control Object section], but it also states: "OMAPI clients connect to the server using TCP/IP, authenticate, and can then examine the server's current status and make changes to it." and "The DHCP server exports the following objects: lease, host, failover-state and group." so not sure, if any (unprivileged) OMAPI client could shut down the server. Hopefully Jiri / someone else more familiar with OMAPI feature could shed more light into this (if each OMAPI client is able to shut down the dhcpd server => just bug or just privileged / authenticated one => potential DoS). Thanks && Regards, Jan. -- Jan iankko Lieskovsky / Red Hat Security Response Team
Current thread:
- CVE Request -- dhcp: DoS (excessive CPU use) by opening an OMAPI connection Jan Lieskovsky (Apr 06)
- Re: CVE Request -- dhcp: DoS (excessive CPU use) by opening an OMAPI connection Jan Lieskovsky (Apr 06)