Some vulnerabilities have been reported in lighttpd, which can be exploited by malicious people to bypass certain security restrictions, cause a DoS (Denial of Service), or potentially to compromise a vulnerable system.

1) An error in the processing of HTTP headers can be exploited to cause a DoS by sending duplicate HTTP headers with a trailing whitespace character.

2) An error in mod_auth can be exploited to cause a DoS by sending requests with the algorithm set to "MD5-sess" and without a cnonce.

3) An error when parsing Auth-Digest headers in mod_auth can potentially be exploited to cause a DoS by sending multiple whitespace characters.

4) An error exists in the mechanism that limits the number of active connections. This can be exploited to cause a DoS.

5) An error exists in the processing of HTTP requests. This can be exploited to access restricted files by adding a "/" to an URL.

6) An error exists in mod_scgi. This can be exploited to cause a DoS by sending a SCGI request and closing the connection while lighttpd processes the request.

7) The return value of "base64_decode" in mod_auth was not checked properly when parsing the credentials for basic authentication, which could lead to accessing uninitialized memory.

8) An error in the header parsing code can lead to access of memory outside of the original boundaries and can cause a memory corruption.

Successful exploitation of this vulnerability can potentially be exploited to execute arbitrary code.

The vulnerabilities are reported in lighttpd-1.4.15. Previous versions may also be affected.

Solution
Update to version 1.4.16.
Further details available in Customer Area

Provided and/or discovered by
1) Olaf van der Spek
2, 3, 7, 8) Stefan Esser
4) pyunyh
5) jay
6) jtate

Changelog
Further details available in Customer Area

Original Advisory
http://www.lighttpd.net/2007/7/24/1-4-16-let-s-ship-it

1) http://trac.lighttpd.net/trac/ticket/1232
2, 3) http://trac.lighttpd.net/trac/changeset/1875
4) http://trac.lighttpd.net/trac/ticket/1216
5) http://trac.lighttpd.net/trac/ticket/1230
6) http://trac.lighttpd.net/trac/ticket/1263
7) http://www.lighttpd.net/assets/2007/7/24/lighttpd_sa2007_04.txt
8) http://www.lighttpd.net/assets/2007/7/24/lighttpd_sa2007_06.txt

Deep Links
Links available in Customer Area