Symlink attack in Mercurial

1) Symlink attack

EUVDB-ID: #VU29241

Risk: Medium

CVSSv3.1: 4 [CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-3902

CWE-ID: CWE-61 - UNIX Symbolic Link (Symlink) Following

Exploit availability: No

Description

The vulnerability allows a remote user to escalate privileges on the system.

The vulnerability exists due to a symlink following issue. A remote user can create a specially crafted symbolic link to and write files outside a repository.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mercurial: 4.0 - 4.8.2

External links

http://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-3902
http://lists.debian.org/debian-lts-announce/2019/04/msg00024.html
http://usn.ubuntu.com/4086-1/
http://www.mercurial-scm.org/wiki/WhatsNew#Mercurial_4.9_.282019-02-01.29

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.