Critical Remote Code Execution in Microsoft Exchange Server (CVE‑2021‑27065) Threatens Enterprise Email
What It Is — Microsoft Exchange Server contains an unspecified vulnerability that enables remote code execution, leveraged as part of the ProxyLogon exploit chain.
Exploitability — Publicly disclosed; active exploitation observed in the wild; CVSS v3.1 base score 9.8 (Critical).
Affected Products — Microsoft Exchange Server 2013, 2016, 2019 (all supported releases).
Why It Matters for Trust & Control Assurance
- Highlights the necessity of a robust vulnerability‑management control that records patch status and proves timely remediation.
- Gaps in this control undermine audit evidence required by multiple frameworks (e.g., NIST CSF Identify, ISO 27001), weakening the trust signal for partners and regulators.
- Continuous documentation of patch deployment feeds the Verisq Trust Center, giving enterprises a defensible posture during third‑party risk assessments.
Recommended Actions
- Inventory every on‑premises and hosted Exchange instance.
- Deploy Microsoft’s security update (KB 5000871 or later) and confirm installation via system inventory tools.
- Enable Exchange’s security baselines and monitor for ProxyLogon‑related Indicators of Compromise.
- Capture patch‑deployment evidence in your control repository to satisfy audit‑readiness requirements.
Source: CISA KEV – CVE‑2021‑27065