CVE-2015-2502
Microsoft Internet Explorer Memory Corruption Vulnerability
Description
CVE-2015-2502 is a memory corruption vulnerability in Microsoft Internet Explorer that allows a remote attacker to execute arbitrary code by convincing a user to visit a specially crafted web page. The vulnerability occurs when Internet Explorer improperly accesses objects in memory, enabling an attacker to corrupt memory in a way that allows arbitrary code execution in the context of the current user. CISA has added CVE-2015-2502 to the Known Exploited Vulnerabilities catalog, confirming active exploitation. With an EPSS score of 90.6% (99.6th percentile), this vulnerability is among the most exploited browser vulnerabilities from the Internet Explorer era.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| microsoft | internet explorer | 7; 8; 9; 10; 11 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
References
- http://twitter.com/Laughing_Mantis/statuses/633839231840841728(Exploit)
- http://twitter.com/Laughing_Mantis/statuses/633839771865886721(Press/Media Coverage)
- http://www.securityfocus.com/bid/76403(Broken Link, Third Party Advisory, VDB Entry)
- http://www.securitytracker.com/id/1033317(Broken Link, Third Party Advisory, VDB Entry)
- http://www.securityweek.com/microsoft-issues-emergency-patch-critical-ie-flaw-exploited-wild(Press/Media Coverage)
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-093(Patch, Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2015-2502(US Government Resource)
Weakness Type
CWE-787: Out-of-bounds Write
CWE-787 describes a weakness where software writes data past the end, or before the beginning, of an intended buffer, leading to memory corruption that can enable arbitrary code execution. In CVE-2015-2502, Internet Explorer improperly handles objects in memory during web page rendering, causing an out-of-bounds write that corrupts memory and allows an attacker to execute arbitrary code.
Learn more: CWE-787 — Out-of-bounds Write
Impact Analysis
CVE-2015-2502 enables remote code execution through Internet Explorer when a user visits a malicious web page, with the attacker's code executing at the privilege level of the logged-in user. If the user has administrator privileges, the attacker gains full system control, including the ability to install programs, modify data, and create new accounts. Even with standard user privileges, the attacker can access all user-accessible files and credentials. The browser-based attack vector makes this vulnerability particularly effective for watering hole attacks and spear-phishing campaigns targeting organizations that still relied on Internet Explorer. The EPSS score of 90.6% (99.6th percentile) confirms extremely high exploitation activity.
Exploit Maturity
CVE-2015-2502 is listed in the CISA Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. The EPSS score of 90.6% (99.6th percentile) places it among the most exploited browser vulnerabilities. The vulnerability was patched in an out-of-band security update from Microsoft, indicating the urgency recognized by the vendor. Exploitation was observed through targeted web-based attacks before the patch was widely deployed.
Remediation
- Migrate away from Internet Explorer entirely as required by CISA KEV — Internet Explorer reached end of life on June 15, 2022, and is no longer supported by Microsoft.
- Apply all available Microsoft security updates to systems that still have Internet Explorer installed, including the out-of-band patch MS15-093 that addresses CVE-2015-2502.
- Disable Internet Explorer through Group Policy and Windows Features on all managed endpoints to prevent accidental use.
- Implement browser isolation solutions for legacy web applications that previously required Internet Explorer.
- Audit systems for signs of compromise from browser-based exploitation, including unexpected downloads, installed programs, or persistence mechanisms.
Technical Details
CVE-2015-2502 is a memory corruption vulnerability in Internet Explorer's rendering engine that occurs when the browser improperly handles objects during page layout processing. When a specially crafted HTML page triggers specific DOM manipulation sequences, Internet Explorer writes data outside the bounds of an allocated buffer, corrupting adjacent memory structures. The attacker can control the corrupted memory to redirect execution flow to shellcode, achieving arbitrary code execution within the Internet Explorer process. Microsoft issued an out-of-band patch (MS15-093) due to the active exploitation, affecting Internet Explorer versions 7 through 11 across all supported Windows versions.
Frequently Asked Questions
Is CVE-2015-2502 being actively exploited?
Yes. CVE-2015-2502 is listed in the CISA KEV catalog with active exploitation confirmed. Microsoft issued an emergency out-of-band patch due to the severity of ongoing attacks.
What products are affected by CVE-2015-2502?
CVE-2015-2502 affects Microsoft Internet Explorer versions 7 through 11 on all supported Windows platforms. Internet Explorer is end-of-life and should be replaced with a modern browser.
How do I fix CVE-2015-2502?
Migrate from Internet Explorer to a modern, supported browser. If IE must remain installed, apply security update MS15-093 and disable IE through Group Policy.
How severe is CVE-2015-2502?
CVE-2015-2502 is a critical memory corruption vulnerability enabling remote code execution through web browsing. Its 99.6th percentile EPSS score confirms extremely high exploitation, and the emergency out-of-band patch reflects the severity recognized by Microsoft.
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