CVE-2012-1889
Microsoft XML Core Services Memory Corruption Vulnerability
Description
CVE-2012-1889 is a memory corruption vulnerability in Microsoft XML Core Services (MSXML) that allows remote attackers to execute arbitrary code. The flaw occurs when MSXML improperly handles objects in memory, enabling an attacker to corrupt memory in a way that redirects program execution to attacker-controlled code. Exploitation can be triggered through a crafted web page or Office document that invokes MSXML. CISA has added CVE-2012-1889 to its Known Exploited Vulnerabilities catalog, and with an EPSS score of 92.8% (99th percentile), this vulnerability has an extremely high probability of active exploitation.
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 | xml core services | 3.0; 4.0; 6.0; 5.0 |
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://technet.microsoft.com/security/advisory/2719615(Vendor Advisory)
- http://www.us-cert.gov/cas/techalerts/TA12-174A.html(Third Party Advisory, US Government Resource)
- http://www.us-cert.gov/cas/techalerts/TA12-192A.html(Third Party Advisory, US Government Resource)
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2012/ms12-043(Patch, Vendor Advisory)
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A15195(Broken Link)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2012-1889(US Government Resource)
Weakness Type
CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer
CVE-2012-1889 exploits a memory corruption condition in Microsoft XML Core Services where the application performs operations that violate memory buffer boundaries. When MSXML processes specially crafted XML data, it fails to properly restrict memory operations, allowing an attacker to corrupt adjacent memory and gain control of program execution flow.
Learn more: CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer
Impact Analysis
CVE-2012-1889 is remotely exploitable through multiple attack vectors — an attacker can craft a malicious web page that triggers the MSXML vulnerability through Internet Explorer, or embed the exploit in an Office document. No authentication is required, and the attack complexity is low since MSXML is widely used across the Windows ecosystem. Successful exploitation results in arbitrary code execution with the privileges of the current user, placing confidentiality, integrity, and availability at full risk. An attacker can steal sensitive data, install persistent backdoors, or use the compromised system as a pivot point for lateral movement. The EPSS score of 92.8% (99th percentile) indicates near-certain exploitation, and the breadth of MSXML's integration across Windows makes the attack surface exceptionally large.
Exploit Maturity
CISA has confirmed active exploitation of CVE-2012-1889 in the wild by adding it to the Known Exploited Vulnerabilities catalog on June 8, 2022. The EPSS score of 92.8% places this vulnerability in the 99th percentile, indicating an extremely high probability of exploitation. CVE-2012-1889 was exploited as a zero-day vulnerability in targeted attacks before Microsoft released a patch, and it was subsequently integrated into multiple exploit kits for broader distribution. While no specific ransomware association has been reported, the vulnerability's versatile attack vectors through both web pages and Office documents make it highly attractive for diverse attack campaigns.
Remediation
- Apply Microsoft security updates immediately: Install the relevant patches for Microsoft XML Core Services as directed by the CISA KEV required action to address the memory corruption vulnerability in MSXML.
- Upgrade or remove vulnerable MSXML versions: Ensure all systems are running patched versions of MSXML 3.0, 4.0, 5.0, and 6.0, or remove unused MSXML installations to reduce the attack surface.
- Restrict MSXML ActiveX controls in Internet Explorer: Configure Internet Explorer kill bits or Group Policy to disable the execution of vulnerable MSXML ActiveX controls, blocking the web-based attack vector.
- Deploy Enhanced Mitigation Experience Toolkit (EMET): On legacy Windows systems, use EMET or Windows Defender Exploit Guard to apply additional exploit mitigations such as DEP enforcement and ROP mitigation for processes that load MSXML.
- Monitor for MSXML exploitation attempts: Configure intrusion detection systems and endpoint monitoring to alert on suspicious XML processing patterns, unexpected MSXML DLL loading, or shellcode execution indicators associated with memory corruption exploits.
Technical Details
CVE-2012-1889 is a memory corruption vulnerability in Microsoft XML Core Services (MSXML) that occurs when the component improperly handles objects in memory during XML data processing. The vulnerability is triggered when MSXML parses specially crafted XML content that causes the engine to access or manipulate memory outside the intended buffer boundaries. This memory corruption condition, classified under CWE-119, allows an attacker to overwrite critical data structures such as function pointers or vtable entries, redirecting program execution to attacker-controlled code. The attack can be delivered via a web page that instantiates a vulnerable MSXML ActiveX control in Internet Explorer, or through an Office document that invokes MSXML for XML processing. Since MSXML is a core Windows component used by numerous applications, the vulnerability has an unusually broad attack surface spanning web browsing, document processing, and any application that relies on MSXML for XML parsing.
Frequently Asked Questions
Is CVE-2012-1889 being actively exploited?
Yes. CISA has confirmed active exploitation of CVE-2012-1889 by adding it to the Known Exploited Vulnerabilities catalog. The EPSS score of 92.8% in the 99th percentile indicates near-certain exploitation. This vulnerability was initially exploited as a zero-day before a patch was available.
What products are affected by CVE-2012-1889?
CVE-2012-1889 affects Microsoft XML Core Services (MSXML) across multiple versions (3.0, 4.0, 5.0, and 6.0) and impacts Windows systems that use MSXML for XML processing. Since MSXML is a core Windows component, the affected surface includes Internet Explorer, Microsoft Office, and other applications.
How do I fix CVE-2012-1889?
Apply the Microsoft security patches for MSXML and ensure all versions are updated. Additionally, restrict MSXML ActiveX controls in Internet Explorer and consider migrating to modern browsers that do not rely on ActiveX technology.
How severe is CVE-2012-1889?
CVE-2012-1889 is a critically severe vulnerability with an EPSS score in the 99th percentile, enabling remote code execution through web pages or Office documents. The widespread use of MSXML across the Windows ecosystem significantly amplifies the overall risk and attack surface.
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