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INetCop Security Advisory #2006-0x82-029
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0x01. Description
Zeroboard is a popular web notice board used in Korea.
INetCop Security found XSS vulnerability in the latest zeroboard version 4.1 pl 7 (2005. 4. 4).
Basically, zeroboard uses the following algorithm so that session may not be abused
by the attack related with cookie. (e.g: cookie spoofing, sniffing)
After login, is part that handle session: –
If IP address is different from present session user's, connection terminates: –
bbs/lib.php:
94 // јјјЗ °ЄА» ГјЕ©ЗПї© ·О±ЧАОА» Гіё®
95 } elseif($HTTP_SESSION_VARS["zb_logged_no"]) {
96
97 // ·О±ЧАО ЅГ°ЈАМ БцБ¤µИ ЅГ°ЈА» іСѕъ°ЕіЄ ·О±ЧАО
This seems to be intercepting cookie hacking.
But, if we take advantage of IP session disablement technique, session bypassing may be possible.
Detailed explanation about the way to exploit this vulnerability is found at the following
reference.
URL: http://x82.inetcop.org/h0me/papers/iframe_tag_exploit.txt (Korean)
As a result, hacker through administrator's web browser exploit code workably become.
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0x02. Vulnerable Packages
Vendor site: http://www.nzeo.com/
Low versions including Zeroboard 4.1 pl 7 (2005. 4. 4) version.
-zb41pl7.tar.Z
Disclosure Timeline:
2003-04.??: Vulnerabilities found.
2006-02.17: 1st vendor contact. (didn't respond)
2006-02.22: 2nd vendor contact. (didn't respond)
2006-02.25: Vendor responded, patch released.
2006-03.12: Public disclosure.
0x03. Exploit
We have 2 `Proof-of-Concept' exploit about this vulnerability.
This XSS vulnerability happens in memo box title and user email, homepage information input.
When administrator logins and checks a user information page, attack code can be achieved,
and there is another way, which injects an attack code in memo title.
After exploit, an attacker can inject PHP code through an administrator web page function.
Through this PHP code injection, the attacker(normal user) can change the password of
administrator,
and take administrator's privilege
To prevent the abuse of this vulnerabilty, INetCop Security will not publish POC code.
0x04. Patch
INetCop Security released temporary patch:
INetCop Security Patch URL: http://inetcop.net/upfiles/Zeroboard-4.1_pl7_patch.tgz
And vendor's patch after INetCop Security advisory:
Vendor Patch URL: http://www.nzeo.com/bbs/zboard.php?id=cgi_bugreport2&no=5406
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Thank you.
P.S: I give thanks to Securityproof that suffer translation.
Korean Advisory URL: http://www.inetcop.org/upfiles/33INCSA.2006-0x82-029-zeroboard.pdf
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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
My World: http://x82.inetcop.org
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