CVE-2015-2502

CVE-2015-2502 is a memory corruption flaw (CWE-119) in Microsoft Internet Explorer in which the browser mishandles specially crafted web content, allowing an attacker to execute code or crash the browser (denial of service). It is triggered when a user of an affected IE version visits an attacker-controlled page, typically delivered via phishing email, a compromised website, or a malicious ad; no special privileges or configuration are required beyond normal web browsing. Successful exploitation yields code execution in the context of the current user, so an admin-rights user exposes the whole system, while the impact is contained for lower-privileged accounts. Affected parties are users of the Microsoft Internet Explorer versions addressed by Microsoft's out-of-band advisory, which in practice means unpatched legacy Windows systems still relying on IE (intranet apps, kiosks, and enterprise fleets using legacy web applications). The flaw is in CISA's Known Exploited Vulnerabilities catalog (added 2022-04-13), confirming in-the-wild exploitation; EPSS assigns a ~51% probability of exploitation within 30 days (99th percentile), and no public PoC is known.

What to do: Apply Microsoft's cumulative Internet Explorer security update from the out-of-band advisory to every Windows system, per the CISA KEV required action, prioritizing internet-facing or multi-user hosts. Migrate any remaining IE-dependent systems and intranet applications to a modern browser (e.g., Microsoft Edge with IE mode), since IE is end-of-life and unpatched instances are a routine attacker entry point. If legacy systems cannot be patched promptly, restrict IE usage and harden browsing (Restricted Sites zone, enhanced security configurations); ransomware linkage is unknown but treat unpatched IE as a general foothold risk.