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Ubuntu 16.04 ESM / 18.04 ESM / 20.04 ESM : Tor vulnerabilities (USN-5036-1)

high Nessus Plugin ID 183153

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Synopsis

The remote Ubuntu host is missing one or more security updates.

Description

The remote Ubuntu 16.04 ESM / 18.04 ESM / 20.04 ESM host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-5036-1 advisory.

 It was discovered that Tor incorrectly handled certain memory operations. A remote attacker could use this issue to cause a denial of service. This issue only affected Ubuntu 18.04 ESM. (CVE-2019-8955)

 It was discovered that Tor did not properly handle the input length to dump_desc() function. A remote attacker could use this issue to cause a denial of service. This issue only affected Ubuntu 16.04 ESM, Ubuntu 18.04 ESM and Ubuntu 20.04 ESM. (CVE-2021-28089)

 It was discovered that Tor did not properly sanitize the relay nickname in dirvote_add_signatures_to_pending_consensus() function. An attacker could possibly use this issue to cause an assertion failure and then cause a denial of service. (CVE-2021-28090)

 It was discovered that Tor did not properly validate the layer hint on half-open streams. A remote attacker could possibly use this issue to bypass the access control, leading to remote code execution.
 This issue only affected Ubuntu 20.04 ESM. (CVE-2021-34548)

 It was discovered that Tor was using an insecure hash function. A remote attacker could use this issue to cause a denial of service. This issue only affected Ubuntu 16.04 ESM, Ubuntu 18.04 ESM and Ubuntu 20.04 ESM. (CVE-2021-34549)

 It was discovered that Tor did not properly manage memory under certain circumstances. If a user were tricked into opening a specially crafted request, a remote attacker could possibly use this issue to cause a crash, resulting in a denial of service, or possibly reading sensitive data. This issue only affected Ubuntu 18.04 ESM and Ubuntu 20.04 ESM. (CVE-2021-34550)

 It was discovered that Tor mishandles the relationship between batch-signature verification and single- signature verification. An attacker could possibly use this issue to cause an assertion failure and then cause a denial of service. This issue only affected Ubuntu 16.04 ESM, Ubuntu 18.04 ESM and Ubuntu 20.04 ESM. (CVE-2021-38385)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the affected tor and / or tor-geoipdb packages.

See Also

https://ubuntu.com/security/notices/USN-5036-1

Plugin Details

Severity: High

ID: 183153

File Name: ubuntu_USN-5036-1.nasl

Version: 1.1

Type: local

Agent: unix

Published: 10/16/2023

Updated: 8/27/2024

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 3.9

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS Score Source: CVE-2021-38385

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.7

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:18.04:-:esm, cpe:/o:canonical:ubuntu_linux:16.04:-:esm, cpe:/o:canonical:ubuntu_linux:20.04:-:esm, p-cpe:/a:canonical:ubuntu_linux:tor-geoipdb, p-cpe:/a:canonical:ubuntu_linux:tor

Required KB Items: Host/cpu, Host/Debian/dpkg-l, Host/Ubuntu, Host/Ubuntu/release

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 10/4/2022

Vulnerability Publication Date: 2/21/2019

Reference Information

CVE: CVE-2019-8955, CVE-2021-28089, CVE-2021-28090, CVE-2021-34548, CVE-2021-34549, CVE-2021-34550, CVE-2021-38385

USN: 5036-1