Symlink traversal in Syncthing

1) Link following

EUVDB-ID: #VU79773

Risk: Medium

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

CVE-ID: CVE-2017-1000420

CWE-ID: CWE-59 - Improper Link Resolution Before File Access ('Link Following')

Exploit availability: No

Description

The vulnerability allows a remote user to overwrite arbitrary files on the system.

The vulnerability exists due to a symlink following issue. A remote user can pass a specially crafted file to the application and overwrite arbitrary files on the system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

syncthing: 0.14.0 - 0.14.35

CPE2.3

• cpe:2.3:a:syncthing.net:syncthing:0.14.0:*:*:*:*:*:*:*
• cpe:2.3:a:syncthing.net:syncthing:0.14.1:*:*:*:*:*:*:*
• cpe:2.3:a:syncthing.net:syncthing:0.14.2:*:*:*:*:*:*:*

External links

https://github.com/syncthing/syncthing/issues/4286

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.