Adversaries Await Absent Attention and Abandoned Assets: Revealing Authentication Blind Spots in Hybrid Microsoft Environments - ToddMaxey/Technical-Documentation GitHub Wiki

Adversaries Await Absent Attention and Abandoned Assets: Revealing Authentication Blind Spots in Hybrid Microsoft Environments

In the evolving threat landscape, the sophistication of an attacker is often rivaled only by the complacency of defenders. Modern hybrid identity environments—those that interlink Azure Active Directory (AAD) with on-premises Active Directory (AD) — are emblematic of this tension. While enterprises increasingly harden cloud infrastructure with conditional access, endpoint detection, and behavioral analytics, the underlying authentication substrate on-premises remains inadequately instrumented and dangerously permissive.

The maxim “Adversaries Await Absent Attention and Abandoned Assets” captures the operational reality of contemporary cyber threats. These are not smash-and-grab intrusions; they are slow burns, conducted by adversaries who exploit systemic neglect — especially when authentication pathways and privileged credentials are insufficiently protected, poorly audited, or silently exposed. Critical vulnerabilities persist not only in outdated protocols like NTLM, but also in the local storage and caching of credentials, the overlooked forensic richness of Netlogon logs, and the failure to enforce credential governance through solutions like Microsoft LAPS.

The Silent Risks of Credential Caching

Credential caching remains one of the most strategically valuable mechanisms exploited by threat actors post-compromise. Once a system is compromised, adversaries routinely target the LSASS (Local Security Authority Subsystem Service) process—a privileged Windows service responsible for managing authentication tokens, cached credentials, and security policy enforcement. Dumping LSASS memory yields:

  • NTLM password hashes
  • Kerberos tickets (TGTs, service tickets)
  • Plaintext credentials (in some configurations)
  • Cached domain logon credentials
  • Security Identifier (SID) to group mappings

This sensitive information can then be used to facilitate Pass-the-Hash (PtH), Pass-the-Ticket (PtT), and overpass-the-hash attacks—enabling lateral movement or domain dominance without repeated authentication prompts.

Common Credential Dumping Techniques

  • ProcDump, Mimikatz, or comsvcs.dll injection to extract LSASS memory
  • MiniDumpWriteDump() via abused LOLBins (e.g., rundll32.exe)
  • Registry extraction of cached credentials under:
HKLM\SYSTEM\CurrentControlSet\Control\Lsa

Especially keys such as:

  • CachedLogonsCount
  • Security Packages
  • LmCompatibilityLevel

These govern how credentials are cached, what protocols are permitted, and whether plaintext credentials are ever exposed in memory. Improper configuration allows an adversary to harvest credentials even when the device is offline, further complicating detection and response.

Netlogon Logging: The Overlooked Telemetry Surface

Despite the ubiquity of LSASS exploitation, defenders routinely overlook another source of high-fidelity authentication telemetry: Netlogon logs. These logs, when enabled, provide visibility into:

  • Inter-domain trust authentications
  • Source IP addresses
  • Machine and service account usage
  • Repeated failed logons—often precursors to brute-force or spray attacks

Yet by default, Netlogon logging is disabled, and its configuration is not available via Group Policy. Instead, it must be explicitly enabled in the Windows Registry:

Registry Path:  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Netlogon\Parameters
Key Name:       DBFlag
Key Type:       REG_DWORD
Key Value:      0x2080FFFF

The corresponding log file is located at:

%SystemRoot%\debug\netlogon.log

This log must be shipped to SIEM platforms and parsed to correlate with Security Event IDs (e.g., 4624, 4776), providing the missing forensic glue that Security logs alone cannot offer.

NTLM Authentication: Legacy Exposure

NTLM continues to be supported in many environments due to historical application requirements and inertia. However, its cryptographic weaknesses and tendency to bypass modern protections (like MFA or device compliance) make it a prime vector for credential replay and session hijacking.

To begin auditing and eventually phasing out NTLM, the following Group Policy settings should be applied:

Computer Configuration > Policies > Windows Settings > Security Settings > Local Policies > Security Options
  • Network security: Restrict NTLM: Audit incoming NTLM traffic → Enable auditing for all accounts
  • Network security: Restrict NTLM: Audit NTLM authentication in this domain → Enable auditing

These settings generate Event IDs 8001–8004 in the Security log, but their utility is vastly enhanced when cross-referenced with Netlogon data.

Local Administrator Password Solution (LAPS): Controlling Privilege Surfaces

In addition to controlling credential exposure in memory, enterprises must address credential reuse across endpoints. Static local administrator passwords—identical across machines—present a catastrophic lateral movement risk. One compromised host grants an attacker local admin rights on dozens more.

Microsoft LAPS enforces randomized, per-machine local administrator credentials, securely stored in Active Directory. It prevents horizontal privilege escalation and closes the most common lateral blast radius vector in internal compromise scenarios.

LAPS GPO Settings (Computer Configuration > Administrative Templates > LAPS):

  • Enable local admin password management → Enabled
  • Name of administrator account to manage → (e.g., Administrator)
  • Password settings → Strong complexity, rotate every 30 days or fewer

Active Directory Schema Requirements:

  • ms-Mcs-AdmPwd and ms-Mcs-AdmPwdExpirationTime attributes
  • Delegated read access to authorized security groups only
  • Auditing of attribute access

Modern LAPS (2023+) also enables Azure integration, Intune management, and secure retrieval logging.

Strategic Directive: Visibility, Control, Containment

Credential hygiene is not a single control—it is a posture. A defensible enterprise requires:

  • Auditing and phasing out NTLM wherever possible
  • Enabling and forwarding Netlogon logs to SIEM
  • Eliminating static local admin passwords via LAPS
  • Restricting LSASS access (e.g., via Credential Guard, LSASS protection)
  • Hardening caching behavior via LSA registry policies

By instrumenting these overlooked controls, security teams reclaim visibility into the very areas adversaries rely upon for stealth and persistence. In hybrid environments, this bridges the critical observability gap between Azure and legacy infrastructure. And in doing so, defenders move from reactive investigation to proactive containment — before persistence is established and trust is eroded.