ASA-2019-00536 – OpenSSL: Fork Protection


Allele Security Alert

ASA-2019-00536

Identifier(s)

ASA-2019-00536, CVE-2019-1549

Title

Fork Protection

Vendor(s)

The OpenSSL Project

Product(s)

OpenSSL

Affected version(s)

OpenSSL version 1.1.1

Fixed version(s)

OpenSSL version 1.1.1d

Proof of concept

Unknown

Description

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.

Technical details

Unknown

Credits

Matt Caswell

Reference(s)

Fork Protection (CVE-2019-1549)
https://www.openssl.org/news/secadv/20190910.txt

drbg: ensure fork-safety without using a pthread_atfork handler
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=1b0fe00e2704b5e20334a16d3c9099d1ba2ef1be

CVE-2019-1549 - Red Hat Customer Portal
https://access.redhat.com/security/cve/CVE-2019-1549

CVE-2019-1549 | SUSE
https://www.suse.com/security/cve/CVE-2019-1549

CVE-2019-1549 in Ubuntu
https://people.canonical.com/~ubuntu-security/cve/CVE-2019-1549.html

CVE-2019-1549
https://security-tracker.debian.org/tracker/CVE-2019-1549

CVE-2019-1549
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-1549

CVE-2019-1549
https://nvd.nist.gov/vuln/detail/CVE-2019-1549

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Last modified: December 6, 2019

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