GHSA-68gr-cmcp-g3mj Directory Traversal in lactate

Not scored Published 14 Jun 2019

Remote attackers can read arbitrary files on the host via directory traversal in the lactate web server, exposing sensitive data.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is GHSA-68gr-cmcp-g3mj?

GHSA-68gr-cmcp-g3mj is a path traversal vulnerability in lactate, published on 14 Jun 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A crafted GET request can be leveraged to traverse the directory structure of a host using the lactate web server package, and request arbitrary files outside of the specified web root. This allows for a remote attacker to gain access to arbitrary files on the filesystem that the process has access to read.

Mitigating factors: Only files that the user running lactate has permission to read will be accessible via this vulnerability.

Proof of concept: Please globally install the lactate package and cd to a directory you wish to serve assets from. Next, run lactate -p 8081 to start serving files from this location.

The following cURL request can be used to demonstrate this vulnerability by requesting the target /etc/passwd file:

curl &#34;http://127.0.0.1:8081/%2e%2e/%2e%2e/%2e%2e/%2e%2e/%2e%2e/etc/passwd&#34;

root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
[...]

Recommendation

As there is currently no fix for this issue selecting an alternative static web server would be the best choice.

Which versions are affected by GHSA-68gr-cmcp-g3mj?

2 open source packages ship an affected version, including lactate.

Package	Affected	Fixed in
`lactate` npm	All versions to `0.13.12`	None
`lactate` npm	All versions to `0.13.12`	None

How do I fix GHSA-68gr-cmcp-g3mj?

No fix has been published for GHSA-68gr-cmcp-g3mj yet. Limit exposure of the affected software until one is available.

Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.

Is GHSA-68gr-cmcp-g3mj being exploited?

There is no known exploitation of GHSA-68gr-cmcp-g3mj in the wild and no public exploit code.