The team that maintains OpenSSL, a key piece of widely used open-source software that’s used to provide encryption for internet communications, disclosed a pair of vulnerabilities on Tuesday that affect the most recent version of the software.
However, after initially rating the vulnerabilities as “critical” in a heads-up advisory last week, the new vulnerabilities have been downgraded to a severity rating of “high,” though administrators are still being urged to patch systems quickly.
The OpenSSL project team disclosed last week that a new vulnerability would be announced on Nov. 1 but did not provide specifics. The announcement had generated significant attention in the cybersecurity community due to the ubiquity of OpenSSL and the massive impact of a previously disclosed critical vulnerability in the software, the Heartbleed vulnerability of 2014.
OpenSSL enables secure internet communications by providing the underlying technology for the HTTPS protocol, now used on 82% of page loads worldwide, according to Firefox. The Heartbleed vulnerability had affected a significant number of major websites and led to attacks including the theft of hundreds of social insurance numbers in Canada, which prompted the shutdown of a tax filing website for the Canada Revenue Agency.
The vulnerability only impacts OpenSSL versions 3.0 and above. Data from cybersecurity vendor Wiz suggests that just 1.5% of OpenSSL instances are affected by the vulnerability.
That’s due at least in part to the relatively recent arrival of OpenSSL 3.0, which was released in September 2021.
“[Given] the fact the vulnerability is primarily client-side, requires the malicious certificate to be signed by a trusted CA (or the user to ignore the warning), and is complex to exploit, I estimate a low chance of seeing in-the-wild exploitation,” security researcher Marcus Hutchins wrote in a post.
The new version of OpenSSL featuring the patch for the vulnerability is OpenSSL 3.0.7.
The pre-announcement on the new version last week was presumably to give organizations time to determine if their applications would be impacted before disclosing the full details on the vulnerabilities, said Brian Fox, co-founder and CTO of software supply chain security vendor Sonatype.
Given the tendency for malicious actors to quickly utilize major vulnerabilities in cyberattacks, many expected that attackers would begin seeking to exploit the issue shortly after the disclosure.
The new vulnerabilities both involve buffer overflow issues, a common bug in software code that can enable an attacker to gain unauthorized access to parts of memory.
In the first vulnerability disclosed on Tuesday, which has been given the tracker CVE-2022-3602, “An attacker can craft a malicious email address to overflow four attacker-controlled bytes on the stack,” the OpenSSL team wrote in the advisory on the issue.
The resulting buffer overflow could lead to a crash or, potentially, remote execution of code, the advisory says.
The severity rating for the vulnerability was downgraded to “high” due to analysis that determined that certain mitigating factors should make it a less-severe issue, according to the OpenSSL advisory on the issue.
“Many platforms implement stack overflow protections which would mitigate against the risk of remote code execution,” the OpenSSL team wrote in the advisory.
One initial analysis suggests that exploiting the vulnerability is more difficult than it could be since the issue occurs after the validation of an encryption certificate.
For the second vulnerability, tracked at CVE-2022-3786, a malicious email address can be utilized to cause a buffer overflow and crash the system, but remote code execution is not mentioned as a potential concern.