CVE-2019-0676
Microsoft Internet Explorer Information Disclosure Vulnerability
Description
CVE-2019-0676 is an information disclosure vulnerability in Microsoft Internet Explorer caused by improper handling of objects in memory. This vulnerability allows an attacker to test for the presence of files on the disk of a targeted user, potentially revealing sensitive information about the system configuration and installed software. CISA has included CVE-2019-0676 in the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. With an EPSS percentile of 95.9%, this vulnerability has a very high probability of being exploited and is commonly used as a reconnaissance step in multi-stage attacks.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:NOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| microsoft | internet explorer | 10; 11 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
References
- http://www.securityfocus.com/bid/106886(Broken Link, Third Party Advisory, VDB Entry)
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-0676(Patch, Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-0676(US Government Resource)
Weakness Type
CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
CWE-200 describes a weakness where a product exposes sensitive information to an actor who is not explicitly authorized to access it. In CVE-2019-0676, Internet Explorer's improper handling of objects in memory allows an attacker to probe the file system and determine whether specific files exist on the victim's machine, leaking information about the system environment.
Learn more: CWE-200 — Exposure of Sensitive Information to an Unauthorized Actor
Impact Analysis
CVE-2019-0676 is an information disclosure vulnerability in Internet Explorer that allows a remote attacker to determine the existence of files on a victim's system. While information disclosure may appear less severe than remote code execution, this type of vulnerability is highly valuable as a reconnaissance tool in targeted attacks. By probing for specific files, an attacker can fingerprint the operating system version, identify installed security software, detect the presence of specific applications, and map out the file system structure — all of which inform subsequent exploitation steps. The attack is network-based, as it can be triggered when a user visits a malicious or compromised website using Internet Explorer. No authentication or special privileges are required, and user interaction is limited to visiting the crafted web page. The EPSS percentile of 95.9% indicates a very high probability of exploitation activity, reflecting the utility of this vulnerability in real-world attack chains.
Exploit Maturity
CISA has confirmed active exploitation of CVE-2019-0676 by including it in the Known Exploited Vulnerabilities catalog with a remediation deadline of June 13, 2022. The EPSS percentile of 95.9% places this vulnerability among the most exploited information disclosure flaws, reflecting its widespread use as a reconnaissance component in targeted attack campaigns. Information disclosure vulnerabilities in Internet Explorer are frequently chained with separate code execution exploits — the information gathered through CVE-2019-0676 helps attackers determine which secondary exploits are most likely to succeed against the specific target environment, making the overall attack chain more reliable.
Remediation
- Apply the security updates provided by Microsoft for Internet Explorer as directed in the associated security advisory. CISA requires remediation by June 13, 2022.
- Consider migrating away from Internet Explorer to a modern, supported browser such as Microsoft Edge, as Internet Explorer has reached end of life and no longer receives security updates.
- If Internet Explorer must remain in use for legacy application compatibility, restrict its usage to only those specific internal applications and block general internet browsing through Group Policy or proxy configurations.
- Deploy network-level protections such as web proxies and content filtering to block access to known malicious domains that may host exploits targeting this vulnerability.
- Monitor endpoint logs for signs of reconnaissance activity, including unusual file system access patterns or browser-based probing attempts that may indicate exploitation of CVE-2019-0676 as part of a broader attack chain.
Technical Details
CVE-2019-0676 stems from a flaw in how Internet Explorer handles objects in memory during page rendering. When processing specially crafted web content, Internet Explorer fails to properly sanitize or restrict access to information about the local file system, allowing an attacker's JavaScript code running in the browser context to test for the existence of specific files on the victim's disk. The vulnerability exploits the browser's interaction with the underlying operating system's file handling mechanisms — by observing differences in browser behavior (such as timing, error responses, or rendering differences) when referencing local file paths, an attacker can infer whether particular files are present. This information leakage occurs without the user's knowledge or explicit consent beyond navigating to the attacker-controlled page. The vulnerability is particularly effective because Internet Explorer's legacy architecture has less strict process isolation and sandboxing compared to modern browsers, allowing browser-level code to interact more directly with the local file system.
Frequently Asked Questions
Is CVE-2019-0676 being actively exploited?
Yes, CVE-2019-0676 is being actively exploited. CISA has included it in the Known Exploited Vulnerabilities catalog, and its EPSS percentile of 95.9% indicates very high exploitation activity. It is commonly used as a reconnaissance step in multi-stage targeted attacks.
What products are affected by CVE-2019-0676?
CVE-2019-0676 affects Microsoft Internet Explorer. Since Internet Explorer has reached end of life, users should migrate to a supported browser. Consult Microsoft's security advisory for the specific affected versions.
How do I fix CVE-2019-0676?
Apply Microsoft's security updates for Internet Explorer. The most effective long-term remediation is migrating to a modern browser like Microsoft Edge, as Internet Explorer no longer receives security updates. If IE must remain for legacy applications, restrict its usage to internal sites only.
How severe is CVE-2019-0676?
CVE-2019-0676 is a significant information disclosure vulnerability with an EPSS percentile of 95.9%. While it does not directly enable code execution, the information it reveals about the target system makes it a valuable component in sophisticated attack chains, effectively increasing the success rate of subsequent exploitation attempts.
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