CVE-2019-0752
Microsoft Internet Explorer Type Confusion Vulnerability
Description
CVE-2019-0752 is a HIGH access of resource using incompatible type ('type confusion') vulnerability affecting Microsoft Internet Explorer, carrying a CVSS 3.1 score of 7.5. A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer Affected products include Microsoft Internet Explorer (11; 10). This CVE is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog with a remediation deadline of 2022-08-15. CISA's KEV catalog confirms ransomware association for this vulnerability. With an EPSS score of 0.92041 (99.7th percentile), this vulnerability demonstrates significant real-world exploitation activity and should be prioritized for immediate remediation.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| microsoft | internet explorer | 11; 10 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
References
- http://packetstormsecurity.com/files/153078/Microsoft-Internet-Explorer-Windows-10-1809-17763.316-Memory-Corruption.html(Exploit, Third Party Advisory, VDB Entry)
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-0752(Patch, Vendor Advisory)
- https://www.zerodayinitiative.com/advisories/ZDI-19-359/(Third Party Advisory, VDB Entry)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-0752(US Government Resource)
Weakness Type
CWE-843: Access of Resource Using Incompatible Type ('Type Confusion')
CVE-2019-0752 is classified under CWE-843 — Access of Resource Using Incompatible Type ('Type Confusion'). Type Confusion occurs when a product allocates or initializes a resource using one type but later accesses that resource using an incompatible type. When the resource is accessed using the wrong type, it may lack expected properties, triggering logical errors. In memory-unsafe languages like C and C++, type confusion can enable out-of-bounds memory access because different types have different sizes and memory layouts. Attackers can exploit type confusion to read or write memory outside intended boundaries, potentially leading to code execution, information disclosure, or system crashes.
In the context of Microsoft Internet Explorer, this weakness is particularly concerning because Type confusion vulnerabilities are particularly dangerous in low-level languages where type information is not enforced at runtime. Accessing memory through an incompatible type can cause reading beyond buffer boundaries (information disclosure), writing beyond buffer boundaries (memory corruption), interpreting data incorrectly (logic errors), and corrupting adjacent memory structures (code execution). In languages with looser type systems (PHP, JavaScript, Perl), type confusion can cause unexpected behavior in comparisons, mathematical operations, or data processing. Organizations using affected versions should understand that this vulnerability class has historically enabled severe compromises across enterprise environments.
Impact Analysis
CVE-2019-0752 carries a CVSS 3.1 score of 7.5 (HIGH) with Unchanged Scope.
Confidentiality (HIGH): Successful exploitation grants the attacker extensive access to sensitive data processed by Microsoft Internet Explorer, including configuration files, credentials, and potentially data from connected systems.
Integrity (HIGH): Attackers can modify critical system files, install backdoors, alter configurations, or deploy malware on affected systems running Microsoft Internet Explorer.
Availability (HIGH): Complete disruption of the affected service or system is possible, including denial of service, system crashes, or rendering the product inoperable.
Scope Unchanged: The vulnerability's scope is Unchanged (U), meaning exploitation is contained within the vulnerable component. The impact, while significant, is limited to the Microsoft Internet Explorer environment itself.
With an EPSS score of 0.92041 (99.7th percentile), this vulnerability ranks among the most likely to be exploited in real-world attacks, underscoring the urgency of remediation.
Exploit Maturity
CVE-2019-0752 has confirmed active exploitation in the wild and is listed in CISA's Known Exploited Vulnerabilities catalog.
Exploit status: This vulnerability has been actively exploited, as confirmed by its inclusion in the KEV catalog. The EPSS score of 0.92041 (99.7th percentile) places it among the most exploited vulnerabilities tracked.
Ransomware association: CISA's KEV catalog confirms a known association between CVE-2019-0752 and ransomware campaigns. Threat actors have leveraged this vulnerability as part of ransomware attack chains for initial access or lateral movement.
Public exploits: Exploit code is publicly available, including references at packetstormsecurity.com. The availability of public exploit code significantly lowers the barrier to exploitation.
KEV deadline: CISA required federal agencies to remediate this vulnerability by 2022-08-15. All organizations should treat this deadline as a strong recommendation for their own remediation timelines.
Remediation
- Apply vendor patches immediately. Apply updates per vendor instructions. Consult the vendor advisory at portal.msrc.microsoft.com for specific patch guidance.
- Verify affected product versions in your environment. Identify all instances of Microsoft Internet Explorer in your infrastructure (affected versions: Microsoft Internet Explorer (11; 10)). Use asset inventory and vulnerability scanning tools to ensure no instances are missed.
- Implement interim mitigations if patching is delayed. If immediate patching is not feasible, apply network-level controls such as restricting access to the affected component, enabling enhanced logging, and monitoring for indicators of compromise.
- Scan for signs of prior exploitation. Given the confirmed active exploitation of this vulnerability, review system logs and security monitoring data for evidence of compromise. Conduct a thorough investigation if any suspicious activity is detected.
- Update detection signatures and monitoring rules. Ensure intrusion detection and prevention systems, endpoint detection tools, and SIEM rules are updated to detect exploitation attempts targeting CVE-2019-0752.
- Conduct a post-remediation review. After patching, verify the fix is effective and document the remediation actions taken. Update your vulnerability management records and assess whether any additional hardening measures are warranted.
Technical Details
CVE-2019-0752 is a HIGH-severity vulnerability in Microsoft Internet Explorer that can be exploited remotely over the network without physical access. The attack complexity is high, meaning successful exploitation requires specific conditions or preparation beyond basic access. No prior authentication or privileges are needed to initiate the attack. User interaction is required, meaning a victim must perform an action such as opening a file, clicking a link, or visiting a website for exploitation to succeed.
Technical mechanism: A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer The underlying flaw relates to access of resource using incompatible type ('type confusion'), where Type Confusion occurs when a product allocates or initializes a resource using one type but later accesses that resource using an incompatible type. When the resource is accessed using the wrong type, it may lack expected properties, triggering logical errors.
CVSS 3.1 vector analysis: The vector reflects an Attack Vector of NETWORK, Attack Complexity of HIGH, Privileges Required of NONE, User Interaction of REQUIRED, Scope UNCHANGED, and impact ratings of HIGH/HIGH/HIGH for Confidentiality/Integrity/Availability respectively. The Unchanged scope means impact is contained within the vulnerable component itself.
Frequently Asked Questions
What is CVE-2019-0752?
CVE-2019-0752 is a HIGH-severity vulnerability (CVSS 7.5) in Microsoft Internet Explorer that a remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer. It is listed in CISA's Known Exploited Vulnerabilities catalog, confirming real-world exploitation. This vulnerability has been associated with ransomware campaigns.
Which products are affected by CVE-2019-0752?
The affected products include Microsoft Internet Explorer (11; 10). Organizations running any of these versions should verify their exposure and prioritize remediation. Check vendor advisories for the complete and most current list of affected versions.
How do I fix CVE-2019-0752?
Apply updates per vendor instructions. Ensure all affected instances of Microsoft Internet Explorer are identified using vulnerability scanning and asset management tools. If immediate patching is not possible, implement network-level mitigations and enhanced monitoring. After patching, verify the fix and scan for indicators of prior compromise.
How severe is CVE-2019-0752?
CVE-2019-0752 is rated HIGH with a CVSS 3.1 score of 7.5. Its EPSS score of 0.92041 places it in the 99.7th percentile for exploitation likelihood. The vulnerability has confirmed active exploitation in the wild and is associated with ransomware campaigns, was required to be remediated by federal agencies by 2022-08-15 per CISA's KEV directive.
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