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Ubuntu Security Notice USN-6435-1
October 18, 2023
openssl vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 18.04 LTS (Available with Ubuntu Pro)
- Ubuntu 16.04 LTS (Available with Ubuntu Pro)
Summary:
OpenSSL could be made to consume resources and cause long delays
if it processed certain input.
Software Description:
- openssl: Secure Socket Layer (SSL) cryptographic library and tools
Details:
It was discovered that OpenSSL incorrectly handled excessively large
Diffie-Hellman parameters. An attacker could possibly use this issue
to cause a denial of service. (CVE-2023-3446)
Bernd Edlinger discovered that OpenSSL incorrectly handled excessively
large Diffie-Hellman parameters. An attacker could possibly use this
issue to cause a denial of service. (CVE-2023-3817)
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 18.04 LTS (Available with Ubuntu Pro):
   libssl1.1                        1.1.1-1ubuntu2.1~18.04.23+esm1
   openssl                         1.1.1-1ubuntu2.1~18.04.23+esm1
Ubuntu 16.04 LTS (Available with Ubuntu Pro):
   libssl1.0.0                     1.0.2g-1ubuntu4.20+esm10
   openssl                         1.0.2g-1ubuntu4.20+esm10
After a standard system update you need to reboot your computer to make
all the necessary changes.
References:
   https://ubuntu.com/security/notices/USN-6435-1
   CVE-2023-3446, CVE-2023-3817