Remote denial of service in Tor

1) Reachable Assertion

EUVDB-ID: #VU83031

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: N/A

CWE-ID: CWE-617 - Reachable Assertion

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a reachable assertion when recording a failed rendezvous circuit on the service side for the MetricsPort. A remote attacker can perform a denial of service attack of the onion service.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Tor: 0.4.8.4 - 0.4.8.8

External links

http://gitlab.torproject.org/tpo/core/tor/-/raw/tor-0.4.8.9/ChangeLog

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to visit a specially crafted website.

Is there known malware, which exploits this vulnerability?

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