Cyber Resilience

CVE-2025-27740

Microsoft Windows Server 2008 r2

Published
08 April 2025
Modified
10 July 2025
Patch / advisory
View advisory
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.033 87th percentile
Risk Priority 69 floored blend · peak EPSS

Summary

CVE-2025-27740 is a high-severity Weak Authentication (CWE-1390) vulnerability in Microsoft Windows Server 2008. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Brute Force (T1110); ranked in the top 13% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to IA-12 (Identity Proofing) and IA-2 (Identification and Authentication (Organizational Users)) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

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

CVE-2025-27740 is a weak authentication vulnerability in Windows Active Directory Certificate Services, assigned CWE-1390 and carrying a CVSS 3.1 base score of 8.8. The flaw permits network-based attacks that require only low-privilege credentials and no user interaction, resulting in complete loss of confidentiality, integrity, and availability on affected systems.

An authorized attacker with valid but limited credentials can exploit the weakness over the network to escalate privileges, obtaining administrative control of the certificate services environment and any resources it protects.

Microsoft has published an advisory for CVE-2025-27740 that includes remediation guidance; the current EPSS score of 0.0117 (peak 0.0171) remains low and shows no material post-disclosure increase.

OWASP Top 10 for Web (2025)

A07:2025 Authentication Failures

EU & UK References

Vulnerability Data

Weak authentication in Windows Active Directory Certificate Services allows an authorized attacker to elevate privileges over a network.

CWE(s)
CWE-1390

Related Threats

MITRE ATT&CK Enterprise Techniques

T1110 Brute Force Credential Access
Adversaries may use brute force techniques to gain access to accounts when passwords are unknown or when password hashes are obtained.
attack.mitre.org →
T1078 Valid Accounts Stealth
Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion.
attack.mitre.org →
T1110.001 Password Guessing Credential Access
Adversaries with no prior knowledge of legitimate credentials within the system or environment may guess passwords to attempt access to accounts.
attack.mitre.org →
T1110.003 Password Spraying Credential Access
Adversaries may use a single or small list of commonly used passwords against many different accounts to attempt to acquire valid account credentials.
attack.mitre.org →
T1078.001 Default Accounts Stealth
Adversaries may obtain and abuse credentials of a default account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion.
attack.mitre.org →
T1078.002 Domain Accounts Stealth
Adversaries may obtain and abuse credentials of a domain account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-49019Same product: Microsoft Windows Server 2008
CVE-2025-50173Same product: Microsoft Windows Server 2008
CVE-2024-38239Same product: Microsoft Windows Server 2008
CVE-2025-26635Same product: Microsoft Windows Server 2019
CVE-2024-49125Same product: Microsoft Windows Server 2008
CVE-2024-49085Same product: Microsoft Windows Server 2008
CVE-2024-49086Same product: Microsoft Windows Server 2008
CVE-2025-59249Same vendor: Microsoft
CVE-2026-55040Same vendor: Microsoft
CVE-2024-38182Same vendor: Microsoft

Affected Assets

microsoft
windows server 2008
all versions, r2
microsoft
windows server 2012
all versions, r2
microsoft
windows server 2016
≤ 10.0.14393.7969
microsoft
windows server 2019
≤ 10.0.17763.7136
microsoft
windows server 2022
≤ 10.0.20348.3453
microsoft
windows server 2022 23h2
≤ 10.0.25398.1551
microsoft
windows server 2025
≤ 10.0.26100.3775

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 9 hardening rules · 7 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V7.6.1
  • V6.3.6
  • V6.4.2
  • V6.4.4

Mitigating Controls (NIST 800-53 r5) AI

IA-12 Identity Proofing good match

Requires identity proofing at appropriate assurance levels before granting accounts, directly addressing insufficient proof of identity.

IA-2 Identification and Authentication (Organizational Users) good match

Requires unique identification and authentication of users, directly stopping weak mechanisms from being used.

IA-3 Device Identification and Authentication good match

Requires device identification and authentication before establishing connections.

IA-8 Identification and Authentication (Non-organizational Users) good match

Extends strong identification and authentication requirements to non-organizational users.

IA-5 Authenticator Management good match

Mandates proper authenticator issuance, management, and strength to ensure claimed identities are verified.

AC-3 Access Enforcement partial match

Enforces access decisions based on authenticated identities, making weak authentication less exploitable.

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.AA-03 full match
prevents

Explicitly requires authentication of users/services/hardware with MFA and password-strength controls.

PR.AA-02 mostly match
prevents

Identity proofing and binding is a core prerequisite for non-weak authentication.

PR.AA-01 partial match
prevents

Credential management directly supports stronger authentication but does not guarantee proof of identity.

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.

A.8.5 Secure authentication full match
prevents

Mandating multi-factor and non-password authentication techniques counters the use of inherently weak single-factor or password-only authentication mechanisms.

A.5.17 Authentication information partial match
prevents

Strong-password and non-reuse requirements raise the bar against weak single-factor authentication that can be exploited via guessing or credential stuffing.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (1 rule)
  • V-248827 OL 8 must not have the rsh-server package installed. prevents CWE-1390
RHEL 7 (1 rule)
  • V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. prevents CWE-1390
RHEL 8 (1 rule)
  • V-230492 RHEL 8 must not have the rsh-server package installed. prevents CWE-1390
Ubuntu 22.04 (1 rule)
  • V-260470 Ubuntu 22.04 LTS, when booted, must require authentication upon booting into single-user and maintenance modes. prevents CWE-1390
Windows 10 (1 rule)
  • V-220865 The Windows Remote Management (WinRM) service must not use Basic authentication. prevents CWE-1390
Windows 11 (1 rule)
  • V-253418 The Windows Remote Management (WinRM) service must not use Basic authentication. prevents CWE-1390

References