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Ubuntu Security Notice USN-6709-1
March 21, 2024

openssl1.0 vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 18.04 LTS (Available with Ubuntu Pro)

Summary:

Several security issues were fixed in OpenSSL.

Software Description:
- openssl1.0: Secure Socket Layer (SSL) cryptographic library and tools

Details:

It was discovered that checking excessively long DH keys or parameters
may be very slow. A remote attacker could possibly use this issue to
cause OpenSSL to consume resources, resulting in a denial of service.
(CVE-2023-3446)

After the fix for CVE-2023-3446 Bernd Edlinger discovered that a large
q parameter value can also trigger an overly long computation during
some of these checks. A remote attacker could possibly use this issue
to cause OpenSSL to consume resources, resulting in a denial of
service. (CVE-2023-3817)

David Benjamin discovered that generating excessively long X9.42 DH
keys or checking excessively long X9.42 DH keys or parameters may be
very slow. A remote attacker could possibly use this issue to cause
OpenSSL to consume resources, resulting in a denial of service.
(CVE-2023-5678)

Bahaa Naamneh discovered that processing a maliciously formatted
PKCS12 file may lead OpenSSL to crash leading to a potential Denial of
Service attack. (CVE-2024-0727)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 18.04 LTS (Available with Ubuntu Pro):
  libssl1.0.0                     1.0.2n-1ubuntu5.13+esm1

After a standard system update you need to reboot your computer to make
all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-6709-1
  CVE-2023-3446, CVE-2023-3817, CVE-2023-5678, CVE-2024-0727