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Ubuntu 16.04 ESM : Libgcrypt vulnerabilities (USN-5080-2)

high Nessus Plugin ID 153514

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Synopsis

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

Description

The remote Ubuntu 16.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-5080-2 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 libgcrypt11-dev, libgcrypt20 and / or libgcrypt20-dev packages.

See Also

https://ubuntu.com/security/notices/USN-5080-2

Plugin Details

Severity: High

ID: 153514

File Name: ubuntu_USN-5080-2.nasl

Version: 1.4

Type: local

Agent: unix

Published: 9/21/2021

Updated: 10/20/2023

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:16.04:-:esm, 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: 5080-2