Remote Code Execution in Microsoft Office Excel (CVE‑2009‑0557) – Object Record Corruption Vulnerability
What It Is – Microsoft Office’s handling of object records contains a corruption flaw that can be triggered by a specially‑crafted Excel file. When the malformed record is processed, memory corruption occurs, allowing an attacker to execute arbitrary code on the victim’s machine.
Exploitability – The vulnerability is listed in CISA’s Known Exploited Vulnerabilities (KEV) catalog, indicating that active exploits are observed in the wild. No public proof‑of‑concept is required; a malicious Excel attachment is sufficient. CVSS v2 base score 7.5 (High).
Affected Products – Microsoft Office (all versions that include Excel) on Windows platforms. Microsoft has released a security update that addresses the issue.
Why It Matters for Trust & Control Assurance
- Demonstrates the need for a vulnerability‑management control that ensures timely identification, risk assessment, and remediation of software flaws.
- Provides a concrete audit artifact: patch‑deployment evidence that can be mapped to control objectives across NIST CSF, ISO 27001, and other frameworks.
- Highlights the importance of continuous monitoring of endpoint software inventories to prove due‑diligence to regulators and enterprise buyers.
Recommended Actions
- Verify that the Microsoft Office security update for CVE‑2009‑0557 is deployed on every endpoint.
- Update your vulnerability‑management process to capture remediation evidence (patch version, deployment date, affected asset list).
- Deploy automated scanning tools that continuously flag unpatched Office installations and generate reports for audit review.
Source: CISA KEV – CVE‑2009‑0557