CVE-2023-21707
Published: 14 February 2023
Summary
CVE-2023-21707 is a high-severity Deserialization of Untrusted Data (CWE-502) vulnerability in Microsoft Exchange Server. Its CVSS base score is 8.8 (High).
Operationally, ranked in the top 1.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
Deeper analysis
CVE-2023-21707 is a remote code execution vulnerability in Microsoft Exchange Server that stems from deserialization of untrusted data (CWE-502). It carries a CVSS 3.1 base score of 8.8 and affects on-premises Exchange deployments reachable over the network.
An authenticated attacker with low privileges can send a crafted request to trigger arbitrary code execution, resulting in full confidentiality, integrity, and availability impact on the affected server without user interaction.
The Microsoft Security Response Center advisory at the referenced URL details the available security updates and configuration guidance for mitigating the issue.
The associated EPSS score currently stands at 0.7202 with a recorded peak of 0.7306, indicating sustained exploitation interest after disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-25874
Vulnerability details
Microsoft Exchange Server Remote Code Execution Vulnerability
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Penetration testing supplies malicious serialized objects, detecting unsafe deserialization and supporting corrective actions.
Evaluation of untrusted data handling (deserialization testing) reveals unsafe processing, which the required remediation process addresses.
Untrusted serialized data can be deserialized and observed inside the chamber, blocking gadget-chain exploitation outside the sandbox.
Validates or rejects untrusted serialized data before deserialization occurs.
Identifies and blocks malicious code introduced through deserialization of untrusted data at system boundaries.
Integrity verification of serialized information can detect tampering before deserialization occurs.
Provenance of associated data allows detection of untrusted sources before deserialization or processing occurs.