CVE-2019-1549

OpenSSL 1.1.1 introduced a rewritten random number generator (RNG). This was intended to include protection in the event of a fork() system call in order to ensure that the parent and child processes did not share the same RNG state. However this protection was not being used in the default case. A partial mitigation for this issue is that the output from a high precision timer is mixed into the RNG state so the likelihood of a parent and child process sharing state is significantly reduced. If an application already calls OPENSSL_init_crypto() explicitly using OPENSSL_INIT_ATFORK then this problem does not occur at all. Fixed in OpenSSL 1.1.1d (Affected 1.1.1-1.1.1c).

Weakness

The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.

Affected Software

Potential Mitigations

• Use a well-vetted algorithm that is currently considered to be strong by experts in the field, and select well-tested implementations with adequate length seeds.
• In general, if a pseudo-random number generator is not advertised as being cryptographically secure, then it is probably a statistical PRNG and should not be used in security-sensitive contexts.
• Pseudo-random number generators can produce predictable numbers if the generator is known and the seed can be guessed. A 256-bit seed is a good starting point for producing a “random enough” number.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/112.html
• https://cwe.mitre.org/data/definitions/485.html
• https://cwe.mitre.org/data/definitions/59.html

References

• https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=1b0fe00e2704b5e20334a16d3c9099d1ba2ef1be
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GY6SNRJP2S7Y42GIIDO3HXPNMDYN2U3A/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZN4VVQJ3JDCHGIHV4Y2YTXBYQZ6PWQ7E/
• https://seclists.org/bugtraq/2019/Oct/1
• https://security.netapp.com/advisory/ntap-20190919-0002/
• https://support.f5.com/csp/article/K44070243
• https://support.f5.com/csp/article/K44070243?utm_source=f5support\u0026amp%3Butm_medium=RSS
• https://usn.ubuntu.com/4376-1/
• https://www.debian.org/security/2019/dsa-4539
• https://www.openssl.org/news/secadv/20190910.txt
• https://www.oracle.com/security-alerts/cpuapr2020.html
• https://www.oracle.com/security-alerts/cpujan2020.html
• https://www.oracle.com/security-alerts/cpujul2020.html
• https://www.oracle.com/security-alerts/cpuoct2020.html
• https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html