CVE-2013-7331
Microsoft Internet Explorer Information Disclosure Vulnerability
Description
CVE-2013-7331 is an information disclosure vulnerability in Microsoft Internet Explorer that allows attackers to query resources loaded into memory, enabling the detection of installed software such as anti-malware applications. By exploiting this flaw through a crafted web page, an attacker can fingerprint the security software installed on a victim's system, which can be used to tailor subsequent attacks by selecting exploits that evade the detected defenses. CISA has confirmed active exploitation of this vulnerability by including it in the Known Exploited Vulnerabilities catalog. With an EPSS percentile of 99.2%, CVE-2013-7331 is among the most frequently exploited vulnerabilities in the entire CVE database.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:LOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| microsoft | internet explorer | 6; 7; 8; 9; 10; 11 |
References
- http://www.fireeye.com/blog/uncategorized/2014/02/operation-snowman-deputydog-actor-compromises-us-veterans-of-foreign-wars-website.html(Third Party Advisory)
- http://www.kb.cert.org/vuls/id/539289(Third Party Advisory, US Government Resource)
- http://www.securitytracker.com/id/1030818(Third Party Advisory, VDB Entry)
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2014/ms14-052(Patch, Vendor Advisory)
- https://soroush.secproject.com/blog/2013/04/microsoft-xmldom-in-ie-can-divulge-information-of-local-drivenetwork-in-error-messages/(Exploit)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2013-7331(US Government Resource)
Weakness Type
Since no specific CWE has been assigned to CVE-2013-7331, the underlying weakness type remains formally unspecified. The vulnerability enables information disclosure through a side-channel that allows web content to detect the presence of locally installed software by querying memory resources. This class of weakness involves improper information exposure where the browser fails to prevent web pages from probing the system's software environment.
Impact Analysis
CVE-2013-7331 is an information disclosure vulnerability that, while not directly leading to code execution, provides attackers with critical reconnaissance data about a target system's security posture. The vulnerability is remotely exploitable through the network, requiring the victim to visit a crafted web page. Once exploited, an attacker can detect which anti-malware products and security tools are installed on the victim's system, enabling them to select appropriate evasion techniques or exploits that bypass the detected protections. This makes CVE-2013-7331 a high-value enabler for multi-stage attacks, where accurate reconnaissance dramatically increases the success rate of subsequent exploitation attempts. The EPSS percentile of 99.2% reflects this vulnerability's extreme utility to attackers, placing it in the top 1% of all CVEs for exploitation likelihood.
Exploit Maturity
CISA has confirmed active exploitation of CVE-2013-7331 by including it in the Known Exploited Vulnerabilities catalog with a remediation deadline of June 15, 2022. The EPSS percentile of 99.2% makes this one of the most actively exploited CVEs in the database, reflecting its widespread use as a reconnaissance tool in real-world attack chains. The ability to remotely detect installed security software makes this vulnerability especially valuable to threat actors conducting targeted attacks, as it allows them to customize their payloads to evade the specific defenses present on each target system.
Remediation
- Apply all available security updates from Microsoft for Internet Explorer as specified in the vendor advisory. CISA's required action is to apply updates per vendor instructions.
- Migrate away from Internet Explorer entirely, as Microsoft has officially ended support for the browser. Transition to a modern, supported browser such as Microsoft Edge, Google Chrome, or Mozilla Firefox.
- Deploy network-level protections such as web content filtering and intrusion detection systems to identify and block known exploit patterns for CVE-2013-7331.
- Implement browser isolation technologies that prevent web content from accessing local system information, adding an additional layer of defense against information disclosure attacks.
- Monitor security logs for indicators of reconnaissance activity, particularly patterns consistent with software fingerprinting attempts from external web content.
Technical Details
CVE-2013-7331 exploits a flaw in Microsoft Internet Explorer that allows web pages to query the presence of resources loaded into memory on the local system. The attack technique leverages the browser's handling of certain resource requests to determine whether specific files or DLLs associated with security products are present in memory. By crafting requests for resources known to be loaded by particular anti-malware applications, an attacker can infer which security products are installed based on the browser's response behavior. This information disclosure does not require any special privileges and is triggered simply by visiting a crafted web page. The vulnerability represents a browser-based side-channel that leaks information about the local software environment to remote web content, violating the intended isolation between web content and the local system.
Frequently Asked Questions
Is CVE-2013-7331 being actively exploited?
Yes, CISA has confirmed active exploitation of CVE-2013-7331 and added it to the Known Exploited Vulnerabilities (KEV) catalog. The EPSS percentile of 99.2% places it among the most exploited CVEs. It is commonly used as a reconnaissance step to detect installed security software before launching further attacks.
What products are affected by CVE-2013-7331?
CVE-2013-7331 affects Microsoft Internet Explorer. While specific version ranges are not detailed in the available data, the vulnerability was addressed in Microsoft security updates released in 2014. All Internet Explorer versions current at the time of disclosure should be considered potentially affected.
How do I fix CVE-2013-7331?
Apply all available Microsoft security updates for Internet Explorer. More importantly, migrate away from Internet Explorer entirely since it has reached end of life. Transitioning to a modern browser eliminates this and many other information disclosure vulnerabilities.
How severe is CVE-2013-7331?
While CVE-2013-7331 is an information disclosure vulnerability rather than a direct code execution flaw, its EPSS percentile of 99.2% reflects its extreme utility in attack chains. The ability to detect installed security software enables attackers to customize subsequent exploits, making this a critical enabler for targeted attacks.
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