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-----BEGIN PGP SIGNED MESSAGE----- =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2000.289 -- FreeBSD-SA-00:57 muh IRC bouncer remote vulnerability 17 October 2000 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: muh Vendor: FreeBSD Ports Collection Operating System: FreeBSD Linux Unix Impact: Execute Arbitrary Code/Commands Access Required: Remote - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- ============================================================================= FreeBSD-SA-00:57 Security Advisory FreeBSD, Inc. Topic: muh IRC bouncer remote vulnerability Category: ports Module: muh Announced: 2000-10-13 Credits: Maxime Henrion <mux@QUALYS.COM> Affects: Ports collection prior to the correction date. Corrected: 2000-09-10 (4.1.1-RELEASE) Vendor status: Updated version released FreeBSD only: NO I. Background muh is an IRC bouncer, a program that allows a host to act as a relay between an IRC client on a local/remote machine and the IRC server. II. Problem Description The muh port, versions 2.05c and before, contains a vulnerability which allows remote users to gain the privileges of the user running muh. This is accomplished by sending a carefully crafted exploit string containing string format operators to a user using muh but who is not connected. When the user reconnects and executes '/muh read', muh will allow the remote attacker to execute arbitrary code as the local user. The muh port is not installed by default, nor is it "part of FreeBSD" as such: it is part of the FreeBSD ports collection, which contains nearly 4000 third-party applications in a ready-to-install format. The ports collections shipped with FreeBSD 3.5.1 and 4.1 contain this problem since it was discovered after the releases, but it was corrected prior to the release of FreeBSD 4.1.1. FreeBSD makes no claim about the security of these third-party applications, although an effort is underway to provide a security audit of the most security-critical ports. III. Impact Remote IRC users can cause arbitrary code to be executed as the user running muh. If you have not chosen to install the muh port/package, then your system is not vulnerable to this problem. IV. Workaround Deinstall the muh port/package, if you you have installed it. V. Solution One of the following: 1) Upgrade your entire ports collection and rebuild the muh port. 2) Deinstall the old package and install a new package dated after the correction date, obtained from: ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-3-stable/irc/muh-2.05c.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/irc/muh-2.05c.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-4-stable/irc/muh-2.05c.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/irc/muh-2.05c.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-5-current/irc/muh-2.05c.tgz NOTE: It may be several days before updated packages are available. 3) download a new port skeleton for the cvsweb port from: http://www.freebsd.org/ports/ and use it to rebuild the port. 4) Use the portcheckout utility to automate option (3) above. The portcheckout port is available in /usr/ports/devel/portcheckout or the package can be obtained from: ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-3-stable/devel/portcheckout-2.0.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/devel/portcheckout-2.0.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-4-stable/devel/portcheckout-2.0.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/devel/portcheckout-2.0.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-5-current/devel/portcheckout-2.0.tgz - -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQCVAwUBOebDhVUuHi5z0oilAQE/3wP+K6oPSZ4jsnLAILhZD3fjdp+3bW7IhDmQ PoXpqSyEypJ6TlP0wLaZwhz1VPThAN9yVaUTzA7W8MVQyKCdIDBWu86WmcZ4CsY9 v7ku77tshEcxza+ggegy9PkSWYDfaQIyGzRyZht280qxn5XUFIeEvXkx+YHKvffo Rm4dlo/akzA= =0bP+ - -----END PGP SIGNATURE----- - --------------------------END INCLUDED TEXT-------------------- This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to use any or all of this information is the responsibility of each user or organisation, and should be done so in accordance with site policies and procedures. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the original authors to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/Information/advisories.html If you believe that your system has been compromised, contact AusCERT or your representative in FIRST (Forum of Incident Response and Security Teams). Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for emergencies. -----BEGIN PGP SIGNATURE----- Version: 2.6.3i Charset: noconv Comment: ftp://ftp.auscert.org.au/pub/auscert/AUSCERT_PGP.key iQCVAwUBOlSNASh9+71yA2DNAQFCdQP+PnizF7HkNikfJr9mPK/DEJQnhA6aCv4A Y7wAWso5QndvSh8xOoeNLkrng+wAIZ6MJ4v0xVASrgA9T4gDQXO2alPG2pzSWkJ+ su1T1hfZrjsmhBlAOl063P2RBfT+7l+mSD73qGgNgnCFAWldnWu/zdcrH68GIaWU Xfg+NewDJD4= =cbwz -----END PGP SIGNATURE-----