CVE-2013-1331
Microsoft Office Buffer Overflow Vulnerability
Description
CVE-2013-1331 is a buffer overflow vulnerability in Microsoft Office that allows remote attackers to execute arbitrary code via crafted PNG data embedded in an Office document. The flaw occurs when the Office application processes a specially crafted PNG image, triggering a buffer overflow that can be leveraged for code execution in the context of the logged-in user. CISA has included CVE-2013-1331 in its Known Exploited Vulnerabilities catalog, confirming real-world exploitation. With an EPSS score of 88.9% (99th percentile), this vulnerability poses a critical risk to organizations still running unpatched versions of Microsoft Office.
KEV Information
CVSS Score
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| microsoft | office | 2003; 2011 |
Multiple CVSS Assessments
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
References
- http://www.us-cert.gov/ncas/alerts/TA13-168A(Third Party Advisory, US Government Resource)
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2013/ms13-051(Patch, Vendor Advisory)
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A16713(Broken Link)
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A16732(Broken Link)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2013-1331(US Government Resource)
Weakness Type
CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CVE-2013-1331 exploits a classic buffer overflow in Microsoft Office's PNG image processing routines, where the application copies image data into a fixed-size buffer without properly verifying that the input data fits within the allocated space. This allows specially crafted PNG data to overwrite adjacent memory and redirect program execution.
Learn more: CWE-120 — Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Impact Analysis
CVE-2013-1331 is remotely exploitable through a crafted Office document — an attacker only needs to convince a victim to open a malicious document containing a specially crafted PNG image. No authentication is required, though user interaction is needed to open the document. Successful exploitation results in arbitrary code execution with the privileges of the current user, which can lead to complete system compromise if the user has administrative rights. Confidentiality, integrity, and availability are all at risk, as an attacker can steal sensitive data, install malware, or disrupt system operations. The EPSS score of 88.9% places this vulnerability in the 99th percentile, indicating near-certain exploitation activity, and organizations should treat this as a critical remediation priority.
Exploit Maturity
CISA has confirmed active exploitation of CVE-2013-1331 in the wild by including it in the Known Exploited Vulnerabilities catalog on June 8, 2022. The EPSS score of 88.9% places this vulnerability in the 99th percentile, indicating a very high probability of exploitation. The document-based attack vector makes this vulnerability particularly attractive for spear-phishing campaigns, where carefully crafted Office documents with malicious PNG payloads can be delivered via email. While no specific ransomware campaigns have been publicly linked to CVE-2013-1331, the remote code execution capability makes it suitable for any post-exploitation scenario.
Remediation
- Apply Microsoft security updates immediately: Install the relevant security patches released by Microsoft that address the PNG processing buffer overflow in affected Office versions, as directed by the CISA KEV required action.
- Upgrade legacy Office installations: If running Office 2003, 2007, or 2010, ensure the latest cumulative security updates are applied, or upgrade to a currently supported Office version that includes modern exploit mitigations.
- Implement Office file validation and Protected View: Ensure that Microsoft Office Protected View is enabled for all documents received from the internet or email attachments, which opens documents in a restricted sandbox and blocks exploitation.
- Deploy email attachment filtering: Configure email gateways to scan and quarantine Office documents with suspicious embedded content, particularly documents with unusual PNG structures or known exploit signatures.
- Monitor for indicators of compromise: Review endpoint detection logs for unusual Office process behavior such as unexpected child process creation, network connections from Office applications, or memory access violations that may indicate buffer overflow exploitation.
Technical Details
CVE-2013-1331 is a buffer overflow vulnerability in Microsoft Office's handling of PNG image data within Office documents. When Office parses a document containing a crafted PNG image with manipulated data fields, the application copies the image data into a stack or heap buffer without verifying that the data length does not exceed the buffer capacity. This classic buffer overflow condition (CWE-120) allows an attacker to overwrite adjacent memory, including return addresses or function pointers, redirecting execution to attacker-controlled shellcode. The vulnerability is triggered during the document rendering process, meaning exploitation occurs as soon as the victim opens the malicious document. Since Office documents are a common business communication format, the social engineering barrier is low, making this an effective vector for targeted attacks.
Frequently Asked Questions
Is CVE-2013-1331 being actively exploited?
Yes. CISA has confirmed active exploitation of CVE-2013-1331 by adding it to the Known Exploited Vulnerabilities catalog. The EPSS score of 88.9% in the 99th percentile indicates a very high likelihood of ongoing exploitation, particularly through spear-phishing campaigns using crafted Office documents.
What products are affected by CVE-2013-1331?
CVE-2013-1331 affects Microsoft Office, specifically the PNG image processing component. Multiple versions of Office including Office 2003, 2007, and 2010 are known to be vulnerable. Organizations should verify their specific Office version against Microsoft's security advisory.
How do I fix CVE-2013-1331?
Apply the relevant Microsoft security updates that address the buffer overflow in Office's PNG handling. Enable Protected View for all externally received documents and ensure email attachment scanning is in place to detect and quarantine malicious Office files.
How severe is CVE-2013-1331?
CVE-2013-1331 is a severe vulnerability with an EPSS score in the 99th percentile, indicating near-certain exploitation. Successful exploitation enables arbitrary code execution with the current user's privileges, which can result in full system compromise, data theft, and malware deployment.
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