Vulnerability Name:

CVE-2020-8516 (CCN-175617)

Assigned:2020-02-01
Published:2020-02-01
Updated:2022-04-18
Summary:** DISPUTED ** The daemon in Tor through 0.4.1.8 and 0.4.2.x through 0.4.2.6 does not verify that a rendezvous node is known before attempting to connect to it, which might make it easier for remote attackers to discover circuit information.
Note: The network team of Tor claims this is an intended behavior and not a vulnerability.
CVSS v3 Severity:5.3 Medium (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N)
4.7 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:U/RL:U/RC:R)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): Low
Integrity (I): None
Availibility (A): None
5.3 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N)
4.7 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:U/RL:U/RC:R)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): Low
Integrity (I): None
Availibility (A): None
CVSS v2 Severity:5.0 Medium (CVSS v2 Vector: AV:N/AC:L/Au:N/C:P/I:N/A:N)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Authentication (Au): None
Impact Metrics:Confidentiality (C): Partial
Integrity (I): None
Availibility (A): None
5.0 Medium (CCN CVSS v2 Vector: AV:N/AC:L/Au:N/C:P/I:N/A:N)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Athentication (Au): None
Impact Metrics:Confidentiality (C): Partial
Integrity (I): None
Availibility (A): None
Vulnerability Type:CWE-noinfo
Vulnerability Consequences:Obtain Information
References:Source: MITRE
Type: CNA
CVE-2020-8516

Source: XF
Type: UNKNOWN
tor-cve20208516-info-disc(175617)

Source: MISC
Type: Mailing List, Vendor Advisory
https://lists.torproject.org/pipermail/tor-dev/2020-February/014146.html

Source: MISC
Type: Mailing List, Vendor Advisory
https://lists.torproject.org/pipermail/tor-dev/2020-February/014147.html

Source: MISC
Type: Third Party Advisory
https://security-tracker.debian.org/tracker/CVE-2020-8516

Source: MISC
Type: Issue Tracking, Vendor Advisory
https://trac.torproject.org/projects/tor/ticket/33129

Source: CCN
Type: The Hacker Factor Blog, Saturday, 1 February 2020
Deanonymizing Tor Circuits

Source: MISC
Type: Exploit, Mitigation, Technical Description, Third Party Advisory
https://www.hackerfactor.com/blog/index.php?/archives/868-Deanonymizing-Tor-Circuits.html

Source: CCN
Type: Tor Web site
Tor Project | Anonymity Online

Vulnerable Configuration:Configuration 1:
  • cpe:/a:torproject:tor:*:*:*:*:*:*:*:* (Version <= 0.4.1.8)
  • OR cpe:/a:torproject:tor:*:*:*:*:*:*:*:* (Version >= 0.4.2.0 and <= 0.4.2.6)

    • * Denotes that component is vulnerable
    Oval Definitions
    Definition IDClassTitleLast Modified
    oval:com.ubuntu.bionic:def:202085160000000
    V
    		CVE-2020-8516 on Ubuntu 18.04 LTS (bionic) - medium.
    2020-02-02
    oval:com.ubuntu.xenial:def:202085160000000
    V
    		CVE-2020-8516 on Ubuntu 16.04 LTS (xenial) - medium.
    2020-02-02
    BACK
    torproject tor *
    torproject tor *