CVE-2019-0989 is a remote code execution (RCE) vulnerability found in the Chakra scripting engine used by the EdgeHTML-based version of Microsoft Edge browser. The vulnerability arises from improper handling of objects in memory, which can lead to memory corruption. An attacker exploiting this flaw can execute arbitrary code within the security context of the current user. If the user has administrative privileges, the attacker could gain full control over the affected system, allowing installation of programs, modification or deletion of data, and creation of new user accounts with full rights. The attack vector is primarily web-based: an attacker can host a malicious website designed to exploit this vulnerability or leverage compromised or user-content-accepting websites to deliver the exploit. Successful exploitation requires user interaction, specifically convincing the user to visit the malicious or compromised site using the vulnerable EdgeHTML-based Microsoft Edge browser. The vulnerability was addressed by Microsoft through a security update that changes how the Chakra engine manages objects in memory to prevent corruption. The CVSS v3.1 base score is 4.2 (medium severity), reflecting the need for user interaction, high attack complexity, and limited impact on confidentiality and integrity (low), with no impact on availability. No known exploits in the wild have been reported, and the vulnerability affects all versions of the EdgeHTML-based Edge browser up to version 1.0.0.

For European organizations, this vulnerability poses a moderate risk primarily to users still operating the legacy EdgeHTML-based Microsoft Edge browser, which has been largely replaced by the Chromium-based Edge. Organizations with legacy systems or environments where this browser remains in use could face targeted attacks via malicious websites or compromised web content. Successful exploitation could lead to unauthorized code execution with the privileges of the logged-in user, potentially resulting in data theft, system compromise, or lateral movement within networks if administrative rights are present. While the medium CVSS score suggests limited impact, the risk escalates in environments where users have elevated privileges or where sensitive data is accessible. The requirement for user interaction reduces the likelihood of widespread automated exploitation but does not eliminate targeted spear-phishing or watering hole attacks. European organizations with web-facing services, especially those in sectors like finance, government, and critical infrastructure, should be cautious as attackers might leverage this vulnerability as part of multi-stage attacks. Additionally, compliance with GDPR and other data protection regulations means that any breach resulting from exploitation could have legal and financial consequences.

1. Immediate application of Microsoft’s security updates that patch the Chakra scripting engine vulnerability is critical. Organizations should verify that all systems have received the relevant patches. 2. Given that the vulnerability affects the EdgeHTML-based Edge browser, organizations should consider migrating users to the Chromium-based Microsoft Edge or alternative modern browsers that are actively supported and patched. 3. Implement strict browser usage policies and restrict legacy browser use to minimize exposure. 4. Employ web filtering and URL reputation services to block access to known malicious or suspicious websites that could host exploit code. 5. Enhance user awareness training focusing on the risks of visiting untrusted websites and recognizing phishing attempts to reduce the likelihood of user interaction with malicious content. 6. Utilize endpoint protection solutions capable of detecting anomalous script execution or memory corruption attempts. 7. Monitor network traffic and logs for unusual activity indicative of exploitation attempts, especially on systems running the vulnerable browser. 8. For environments where legacy browser use is unavoidable, consider sandboxing or isolating browser sessions to limit potential damage from exploitation.