Security Resilience

CVE-2023-21557

Memory Safety in Microsoft Windows 10 1809

Published
10 January 2023
Modified
21 November 2024
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.020 81th percentile
Risk Priority 64 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

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, exploitation aligns with the MITRE ATT&CK technique LSA Secrets (T1003.004); ranked in the top 19% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

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

Vulnerability Data

Windows Lightweight Directory Access Protocol (LDAP) Denial of Service Vulnerability

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1003.004 LSA Secrets Credential Access
Adversaries with SYSTEM access to a host may attempt to access Local Security Authority (LSA) secrets, which can contain a variety of different credential materials, such as credentials for service accounts.
T1003.005 Cached Domain Credentials Credential Access
Adversaries may attempt to access cached domain credentials used to allow authentication to occur in the event a domain controller is unavailable.
T1003.006 DCSync Credential Access
Adversaries may attempt to access credentials and other sensitive information by abusing a Windows Domain Controller's application programming interface (API)(Citation: Microsoft DRSR Dec 2017) (Citation: Microsoft GetNCCChanges) (Citati…
T1003.008 /etc/passwd and /etc/shadow Credential Access
Adversaries may attempt to dump the contents of <code>/etc/passwd</code> and <code>/etc/shadow</code> to enable offline password cracking.
T1006 Direct Volume Access Stealth
Adversaries may directly access a volume to bypass file access controls and file system monitoring.
T1008 Fallback Channels Command And Control
Adversaries may use fallback or alternate communication channels if the primary channel is compromised or inaccessible in order to maintain reliable command and control and to avoid data transfer thresholds.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-21754Same product: Microsoft Windows 10 1607
CVE-2023-21730Same product: Microsoft Windows 10 1607
CVE-2023-21561Same product: Microsoft Windows 10 1607
CVE-2023-21802Same product: Microsoft Windows 10 1607
CVE-2023-24908Same product: Microsoft Windows 10 1607
CVE-2023-23405Same product: Microsoft Windows 10 1607
CVE-2023-21823Same product: Microsoft Windows 10 1607
CVE-2023-21797Same product: Microsoft Windows 10 1607
CVE-2023-23385Same product: Microsoft Windows 10 1607
CVE-2023-23410Same product: Microsoft Windows 10 1607

Affected Assets

microsoft
windows 10 1607
all versions
microsoft
windows 10 1809
all versions
microsoft
windows 10 20h2
all versions
microsoft
windows 10 21h2
all versions
microsoft
windows 10 22h2
all versions
microsoft
windows 11 21h2
all versions
microsoft
windows 11 22h2
all versions
microsoft
windows 7
all versions
microsoft
windows 8.1
all versions
microsoft
windows rt 8.1
all versions
+5 more product configuration(s) — see NVD for full list

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V5.2.6

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.

addresses: CWE-400

Limiting concurrent sessions directly prevents uncontrolled resource consumption by capping the number of active sessions per user or account.

addresses: CWE-400

Analysis identifies uncontrolled resource consumption indicative of denial-of-service or abuse attempts.

addresses: CWE-400

Contingency plan testing includes resource exhaustion scenarios to verify recovery, making it harder for attackers to sustain exploits that cause uncontrolled consumption.

addresses: CWE-400

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.

addresses: CWE-400

Alternate site allows resumption of operations if resource exhaustion at the primary site is exploited to cause unavailability.

addresses: CWE-400

Alternate telecommunications services enable resumption of essential functions when primary services become unavailable due to uncontrolled resource consumption.

addresses: CWE-400

The team can analyze and respond to resource exhaustion incidents, reducing the impact of attacks that exploit uncontrolled consumption weaknesses.

addresses: CWE-400

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.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 partial match
blocks

Secure SDLC practices directly require use of safe arithmetic, bounds checks, and testing that prevent integer overflows.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

removes
removes
removes
removes
finds

Pre-agreed severity-based prioritization and resource allocation during incident triage reduce the likelihood that an attacker-induced resource exhaustion will overwhelm the organization before corrective action is taken.

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-400, a class-level weakness. Rules are authored against its narrower children: CWE-770.

References