Re: majordomo 1.94.5 does not fix all vulnerabilities

From: Chan Wilson (cwilsonat_private)
Date: Tue Jan 25 2000 - 03:20:28 PST

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    Brock Sides <bsidesat_private> spaketh thusly on Mon, 24 Jan 2000 14:55:42 -0600
    	about majordomo 1.94.5 does not fix all vulnerabilities...
    > Whereas majordomo 1.94.5 does fix the bug in resend, discovered by Brock
    > Tellier, that permits execution of arbitrary code as user majordomo, it
    > apparently does not fix the other bug in the script majordomo, that
    > permits execution of arbitrary config files as user majordomo:
    
    Correct.  That is far better addressed at a o/s level by protecting
    the directory that the majordomo code lives in.  A security note has
    been added to the top of the INSTALL document that attempts to
    highlight this matter:
    
    	** SECURITY ALERT **
    	
    	   The default installation of Majordomo, including the checks that
    	config-test does, WILL NOT RESULT IN A SECURE INSTALLATION.  In
    	particular, the majordomo home directory and the "wrapper" program
    	are, by default, accessible to any user.  These open privileges can be
    	(mis)used to change list membership, list configuration details, forge
    	email, perhaps even create and/or delete lists, and anything else that
    	the majordomo user has permissions to do.
    	
    	   If Majordomo is *NOT* installed on a secured system with controlled
    	access (and if you are paranoid, even if it is), you will need to take
    	additional steps to prevent access to the majordomo directories.
    	Usually, changing the privileges of the majordomo home directory to be
    	0750 fixes these problems, but creates the additional burden of
    	needing to configure the MTA (sendmail, qmail, exim) properly so that
    	it can read and execute "wrapper".  Such configuration is beyond the
    	scope of this install document, and is left to the FAQ (Doc/FAQ,
    	Doc/majordomo-faq.html) and the support group
    	majordomo-usersat_private to answer.
    	
    	** SECURITY ALERT **
    
    While it is possible, as has been posted earlier, to patch all the
    code that uses the -C configuration file flag, *and* patch resend to
    only allow execution of code in specific directories, *and* rework
    code so it knows where to find the relocated code, it is far easier to
    simply prevent access to the majordomo directory (including access
    log, list configuration, membership, etc) which gives security from
    both execution of arbitrary code *and* information security for the
    distribution lists.
    
    --Chan
    	majordomo maintainer.
    



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