Path traversal in Slack Nebula

1) Path traversal

EUVDB-ID: #VU26721

Risk: Medium

CVSSv4.0: 4.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-11498

CWE-ID: CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform directory traversal attacks.

The vulnerability exists due to input validation error when processing directory traversal sequences in "tun_darwin.go" and "tun_windows.go" file. A remote authenticated attacker can send a specially crafted HTTP request and read arbitrary files on the system.

Successful exploitation of this vulnerability may lead to remote code execution.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Nebula: 1.0.0 - 1.1.0

CPE2.3

• cpe:2.3:a:slack_technologies:nebula:1.0.0:*:*:*:*:*:*:*
• cpe:2.3:a:slack_technologies:nebula:1.1.0:*:*:*:*:*:*:*

External links

https://www.pwn3d.org/posts/7918501-slack-nebula-relative-path-bug-bounty-disclosure
https://github.com/slackhq/nebula/pull/191

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.