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TUCoPS :: Web :: Apps :: mailman2.htm

Mailman fatal() weakness



Vulnerability

    mailman

Affected

    mailman 2.0beta3, 2.0beta4

Description

    Stan Bubrouski  found following.   Most directories  in a  mailman
    install are  mode 2755  as are  most of  the binaries and scripts.
    Many configurations are 664 allowing  a local user to change  list
    configurations and even read the adm.pw passwd file.  Additionally
    besides being  able to  read public  and private  data along  with
    passwds, a malicious user could replace binaries and scripts in  a
    mailman installation because they are writable by group mailman.

    The mailman package comes with a sgid program named wrapper.  This
    program contains a function named fatal() which is used to display
    error messages.  Unfortunately it fails to send the correct amount
    of  arguments  to  the  fprintf(3)  function allowing users to add
    formatting which could  be used to  insert and execute  code under
    group  mailman.   fatal()  is  called  when  invalid arguments are
    provided and  in such  a case,  the invalid  arguments are sent to
    fprintf without being formatted, the same goes for argv[0].

    Example:

        [user@king user]$ ls -al /usr/share/mailman/mail/wrapper
        -rwxr-sr-x    1 mailman  mailman     36290 Jul  1 06:48
        /usr/share/mailman/mail/wrapper
        [user@king user]$ cd /usr/share/mailman/mail
        [user@king mail]$ ls -al
        total 39
        drwxrwsr-x    2 mailman  mailman      1024 Jul 12 19:29 .
        drwxrwsr-x   16 mailman  mailman      1024 Jul 27 20:13 ..
        -rwxr-sr-x    1 mailman  mailman     36290 Jul  1 06:48 wrapper
        [user@king mail]$ ./wrapper
        Usage: ./wrapper program [args...]
        [user@king mail]$ ./wrapper %s
        Illegal command: Illegal command: %s[user@king mail]$ ./wrapper %s%s
        Illegal command: Illegal command: %s%s=@X>@[user@king
        mail]$ ./wrapper %s%s%s
        Segmentation fault
        [user@king mail]$ ./wrapper %s%u%p
        Illegal command: Illegal command: %s%u%p32212244600x656c6c49[user@king mail]$
        [user@king mail]$ doexec ./wrapper %s
        Usage: Usage: %s program [args...]
          program [args...]
        [user@king mail]$ doexec ./wrapper %s%s
        Usage: Usage: %s%s program [args...]
        =@X>@ program [args...]
        [user@king mail]$ doexec ./wrapper %s%p
        Usage: Usage: %s%p program [args...]
        0xbffffc0c program [args...]
        [user@king mail]$ doexec ./wrapper %s%S%u
        Usage: Usage: %s%S%u program [args...]
        [user@king mail]$ doexec ./wrapper %s%s
        Usage: Usage: %s%s program [args...]
        =@X>@ program [args...]
        [user@king mail]$ doexec ./wrapper %s%s%s
        Segmentation fault
        [user@king mail]$

Solution

    Patch:

    diff -u -r ./cgi-wrapper.c.orig ./cgi-wrapper.c
    --- ./cgi-wrapper.c.orig        Tue Mar 21 01:26:41 2000
    +++ ./cgi-wrapper.c     Fri Jul 28 00:17:42 2000
    @@ -53,7 +53,7 @@
             fake_argv[2] = script;

             status = run_script("driver", 3, fake_argv, env);
    -       fatal(logident, status, "%s", strerror(errno));
    +       fatal(logident, status, "%s\n", strerror(errno));
             return status;
      }

    diff -u -r common.c.orig ./common.c
    --- ./common.c.orig     Mon May 22 14:59:31 2000
    +++ ./common.c  Thu Jul 27 23:58:12 2000
    @@ -108,7 +108,7 @@
                     printf("</pre>\n");
             }
             else
    -               fprintf(stderr, log_entry);
    +               fprintf(stderr, "%s", log_entry);
      #endif /* HELPFUL */
             exit(exitcode);
      }
    diff -u -r ./mail-wrapper.c.orig ./mail-wrapper.c
    --- ./mail-wrapper.c.orig       Tue Mar 21 01:26:41 2000
    +++ ./mail-wrapper.c    Fri Jul 28 00:16:34 2000
    @@ -67,13 +67,13 @@

             if (!check_command(argv[1]))
                     fatal(logident, MAIL_ILLEGAL_COMMAND,
    -                     "Illegal command: %s", argv[1]);
    +                     "Illegal command: %s\n", argv[1]);

             check_caller(logident, parentgid);

             /* If we got here, everything must be OK */
             status = run_script(argv[1], argc, argv, env);
    -       fatal(logident, status, "%s", strerror(errno));
    +       fatal(logident, status, "%s\n", strerror(errno));
             return status;
      }

    The patch  fixes fatal()  and also  adds newlines  to some fatal()
    calls because fatal() does not tack them on and as you can see  in
    the example above, the lack of newlines in some calls make  errors
    harder to read.   Stan made the  patch using the  latest CVS  tree
    but it should apply to beta3 and beta4 releases as well.

    Also, Mailman 2.0 beta 5 was  released.  This is an important  bug
    fix  release  that  should  once  and  for  all  solve the "cookie
    re-authentication" bug.  It also fixes a small security hole  that
    could be  exploited by  clever local  users to  gain group mailman
    permission.  As usual, you can get the tarball from SourceForge:

        http://download.sourceforge.net/mailman/mailman-2.0beta5.tgz

    or list.org

        http://www.list.org/mailman.tar.gz

    For Conectiva Linux:

        ftp://ftp.conectiva.com.br/pub/conectiva/atualizacoes/4.1/i386/mailman-2.0beta5-1cl.i386.rpm
        ftp://ftp.conectiva.com.br/pub/conectiva/atualizacoes/4.2/i386/mailman-2.0beta5-1cl.i386.rpm
        ftp://ftp.conectiva.com.br/pub/conectiva/atualizacoes/5.0/i386/mailman-2.0beta5-1cl.i386.rpm
        ftp://ftp.conectiva.com.br/pub/conectiva/atualizacoes/5.1/i386/mailman-2.0beta5-1cl.i386.rpm

        ftp://ftp.conectiva.com.br/pub/conectiva/atualizacoes/4.1/SRPMS/mailman-2.0beta5-1cl.src.rpm
        ftp://ftp.conectiva.com.br/pub/conectiva/atualizacoes/4.2/SRPMS/mailman-2.0beta5-1cl.src.rpm
        ftp://ftp.conectiva.com.br/pub/conectiva/atualizacoes/5.0/SRPMS/mailman-2.0beta5-1cl.src.rpm
        ftp://ftp.conectiva.com.br/pub/conectiva/atualizacoes/5.1/SRPMS/mailman-2.0beta5-1cl.src.rpm

    For Red Hat:

        ftp://updates.redhat.com/secureweb/3.2/i386/mailman-2.0beta5-1.i386.rpm
        ftp://updates.redhat.com/secureweb/3.2/SRPMS/mailman-2.0beta5-1.src.rpm

    SuSE-Linux either  does not  contain these  packages or  the files
    therein causing the publically announced security vulnerabilities.

    Linux-Mandrake  does  not  ship  with  the  mailman package and is
    therefore not vulnerable to this exploit.

    Debian GNU/Linux 2.1  alias slink comes  with version 1.0  that is
    not vulnerable.   Debian 2.2 alias  potato comes with  version 1.1
    that is not  vulnerable.  Debian  Unstable alias woody  is not yet
    released and reflects the current development release.  Fixes  are
    currently available for Intel ia32 and Motorola 680x0.  Fixes  for
    other  architectures  will  be  available  soon.  In doubt, please
    recompile the package from source on your own:

        ftp://ftp.debian.org/debian/dists/woody/main/source/mail/mailman_2.0beta5-1.diff.gz
        ftp://ftp.debian.org/debian/dists/woody/main/source/mail/mailman_2.0beta5-1.dsc
        ftp://ftp.debian.org/debian/dists/woody/main/source/mail/mailman_2.0beta5.orig.tar.gz
        
        ftp://ftp.debian.org/debian/dists/woody/main/binary-i386/mail/mailman_2.0beta5-1.deb
        ftp://ftp.debian.org/debian/dists/woody/main/binary-m68k/mail/mailman_2.0beta5-1.deb


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