#VU30428 Improper Handling of Exceptional Conditions in Tor - CVE-2015-2688

Vulnerability identifier: #VU30428

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2015-2688

CWE-ID: N/A

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 perform a denial of service (DoS) attack.

buf_pullup in Tor before 0.2.4.26 and 0.2.5.x before 0.2.5.11 does not properly handle unexpected arrival times of buffers with invalid layouts, which allows remote attackers to cause a denial of service (assertion failure and daemon exit) via crafted packets.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Tor: 0.2.5.1 - 0.2.5.10

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External links
https://lists.torproject.org/pipermail/tor-talk/2015-March/037281.html
https://trac.torproject.org/projects/tor/ticket/15083

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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.