#VU41438 Input validation error in Tor - CVE-2014-5117

Vulnerability identifier: #VU41438

Vulnerability risk: Medium

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2014-5117

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Tor
Client/Desktop applications / Web browsers

Vendor: tor.eff.org

Description

The vulnerability allows a remote non-authenticated attacker to read and manipulate data.

Tor before 0.2.4.23 and 0.2.5 before 0.2.5.6-alpha maintains a circuit after an inbound RELAY_EARLY cell is received by a client, which makes it easier for remote attackers to conduct traffic-confirmation attacks by using the pattern of RELAY and RELAY_EARLY cells as a means of communicating information about hidden service names.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Tor: 0.0.2 - 0.2.5.5

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External links
https://secunia.com/advisories/60084
https://secunia.com/advisories/60647
https://blog.torproject.org/blog/tor-security-advisory-relay-early-traffic-confirmation-attack
https://lists.torproject.org/pipermail/tor-announce/2014-July/000093.html
https://lists.torproject.org/pipermail/tor-announce/2014-July/000094.html
https://lists.torproject.org/pipermail/tor-talk/2014-July/034180.html
https://trac.torproject.org/projects/tor/ticket/1038

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Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

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