Remote denial of service in Tor exit relays

1) Resource exhaustion

EUVDB-ID: #VU84584

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-400 - Resource exhaustion

Exploit availability: No

Description

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

The vulnerability exists due to improper management of internal resources in exit relays. A remote attacker can trigger resource exhaustion and perform a denial of service (DoS) attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Tor: 0.4.8.4 - 0.4.8.9

External links

http://forum.torproject.org/t/security-release-0-4-8-10/10536
http://forum.torproject.org/t/tor-relays-exit-operators-on-the-0-4-8-x-series-please-upgrade-to-0-4-8-10-asap/10537

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.