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Ubuntu 18.04 LTS / 20.04 LTS : Libgcrypt vulnerabilities (USN-5080-1)

high Nessus Plugin ID 153447

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Synopsis

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

Description

The remote Ubuntu 18.04 LTS / 20.04 LTS / 21.04 host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-5080-1 advisory.

 - Libgcrypt before 1.8.8 and 1.9.x before 1.9.3 mishandles ElGamal encryption because it lacks exponent blinding to address a side-channel attack against mpi_powm, and the window size is not chosen appropriately. This, for example, affects use of ElGamal in OpenPGP. (CVE-2021-33560)

 - The ElGamal implementation in Libgcrypt before 1.9.4 allows plaintext recovery because, during interaction between two cryptographic libraries, a certain dangerous combination of the prime defined by the receiver's public key, the generator defined by the receiver's public key, and the sender's ephemeral exponents can lead to a cross-configuration attack against OpenPGP. (CVE-2021-40528)

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

Solution

Update the affected packages.

See Also

https://ubuntu.com/security/notices/USN-5080-1

Plugin Details

Severity: High

ID: 153447

File Name: ubuntu_USN-5080-1.nasl

Version: 1.4

Type: local

Agent: unix

Published: 9/16/2021

Updated: 10/16/2023

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: 4.1

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

CVSS Score Source: CVE-2021-33560

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 7

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

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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:libgcrypt-mingw-w64-dev, p-cpe:/a:canonical:ubuntu_linux:libgcrypt11-dev, p-cpe:/a:canonical:ubuntu_linux:libgcrypt20, p-cpe:/a:canonical:ubuntu_linux:libgcrypt20-dev

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: 9/16/2021

Vulnerability Publication Date: 6/8/2021

Reference Information

CVE: CVE-2021-33560, CVE-2021-40528

USN: 5080-1