CVE-2023-21557
Published: 10 January 2023
Summary
CVE-2023-21557 is a high-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Microsoft Windows 10 1809. Its CVSS base score is 7.5 (High).
Operationally, ranked in the top 9.9% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
Deeper analysis
Windows Lightweight Directory Access Protocol (LDAP) contains a denial-of-service vulnerability tracked as CVE-2023-21557. The flaw affects the LDAP service component in supported Windows versions and is characterized by CWE-190 and CWE-400, indicating an integer overflow that can lead to uncontrolled resource consumption. It carries a CVSS 3.1 base score of 7.5 reflecting network attack vector, low complexity, and no required privileges or user interaction, with the primary impact being high availability loss.
An unauthenticated remote attacker can send specially crafted LDAP requests over the network to trigger the flaw, causing the LDAP service to become unresponsive and denying service to legitimate directory clients. Because the vulnerability requires no authentication, any host able to reach an exposed LDAP interface can exploit it.
Microsoft’s security advisory at msrc.microsoft.com details the affected Windows builds and supplies the corresponding security update that resolves the issue; administrators are advised to apply the patch through normal update channels to eliminate the exposure. The associated EPSS score has remained flat at 0.0512 with no material increase since disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-25724
Vulnerability details
Windows Lightweight Directory Access Protocol (LDAP) 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.
Limiting concurrent sessions directly prevents uncontrolled resource consumption by capping the number of active sessions per user or account.
Analysis identifies uncontrolled resource consumption indicative of denial-of-service or abuse attempts.
Contingency plan testing includes resource exhaustion scenarios to verify recovery, making it harder for attackers to sustain exploits that cause uncontrolled consumption.
Updated contingency plans include current procedures to detect, contain, and recover from resource exhaustion, limiting an attacker's ability to sustain impact from uncontrolled consumption.
Alternate site allows resumption of operations if resource exhaustion at the primary site is exploited to cause unavailability.
Alternate telecommunications services enable resumption of essential functions when primary services become unavailable due to uncontrolled resource consumption.
The team can analyze and respond to resource exhaustion incidents, reducing the impact of attacks that exploit uncontrolled consumption weaknesses.
Timely maintenance support and spare parts enable rapid recovery from failures induced by uncontrolled resource consumption, shortening the impact window of denial-of-service attacks.