CVE-2023-21818
Published: 14 February 2023
Summary
CVE-2023-21818 is a high-severity Improper Input Validation (CWE-20) vulnerability in Microsoft Windows Server 2008. Its CVSS base score is 7.5 (High).
Operationally, ranked in the top 3.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
Deeper analysis
CVE-2023-21818 is a denial-of-service vulnerability in Windows Secure Channel, the component responsible for implementing TLS and other cryptographic protocols on Windows systems. It carries a CVSS 3.1 base score of 7.5 with a vector indicating network attackability, low complexity, no required privileges or user interaction, and high impact on availability.
An unauthenticated remote attacker can send specially crafted network traffic to a vulnerable Windows host and trigger the flaw, causing the Secure Channel service to stop responding and thereby disrupting any applications or services that rely on it for secure communications.
Microsoft has published guidance for the issue in its Security Response Center update guide, which includes details on available patches and recommended actions for affected Windows versions.
The associated EPSS score reached a peak of 0.4151, indicating a period of elevated exploitation interest after disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-25984
Vulnerability details
Windows Secure Channel Denial of Service 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.
Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.
Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.
Directly implements checks on information inputs to reject invalid data before processing.
Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.