BP-026: Privilege Escalation via Vulnerable On-Prem AD Sync Paths
A critical hybrid identity security pattern where attackers exploit weaknesses in on-premises Active Directory to escalate privileges in Azure AD/Entra ID through directory synchronization mechanisms.
What This Breach Pattern Is
This breach pattern exploits fundamental trust relationships in hybrid identity architectures. When Azure AD Connect synchronizes directories, it implicitly trusts the on-premises Active Directory as the source of truth. Attackers weaponize this trust by compromising on-prem identities, then leveraging sync mechanisms to escalate privileges in the cloud environment.
The attack creates a dangerous blast-radius escalation path where local AD compromise directly translates to cloud administrative access. This makes hybrid sync infrastructure a prime target for sophisticated adversaries seeking persistent, high-privilege cloud access.
Key Risk Factor
Entra ID inherently trusts on-premises directory data, creating an implicit privilege escalation pathway that bypasses cloud-native security controls.
Hybrid Environment Vulnerabilities
Sync Configuration Flaws
Misconfigured Azure AD Connect sync rules
Excessive sync scope including privileged groups
Weak filtering of sensitive attributes
Identity Architecture Gaps
Lingering hybrid service accounts
Shadow admin groups synced unintentionally
Outdated emergency access paths
Privilege Mapping Issues
On-prem groups mapped to cloud roles
Excessive permissions on sync connectors
Weak on-prem admin groups synced to Entra
These vulnerabilities compound to create multiple attack vectors. Compromise of any single component—whether an on-prem user, AD administrator, synced privileged group, Azure AD Connect server, or sync connector credentials—can trigger full cloud privilege escalation.
Attacker Objectives
Primary Goals
Escalate to Entra admin roles via on-prem AD compromise
Impersonate administrators using synced identities
Modify directory objects that propagate upward to cloud
Weaken password and MFA policies at the source
Advanced Tactics
Create persistent access via hybrid service accounts
Compromise cloud applications mapped to hybrid groups
Establish shadow admins on-prem that auto-sync to cloud
Maintain stealth by operating within normal sync patterns
Critical Insight: Hybrid escalation represents one of the stealthiest privilege escalation vectors in modern identity infrastructure, often evading cloud-native detection mechanisms entirely.
Enabling Misconfigurations
Specific identity misconfigurations create exploitable conditions for this breach pattern. Understanding these weaknesses is essential for effective defense.
MC-241: Over-Permissioned AD Sync Scope
Excessive privileged AD groups included in synchronization scope, expanding attack surface and enabling unintended privilege inheritance in cloud environment.
MC-242: Weak Azure AD Connect Server Security
Sync servers lack proper hardening, exposed to network attacks, or running with excessive service account privileges that enable credential extraction.
MC-243: Hybrid Emergency Access Backdoors
Legacy AD groups remain mapped to cloud admin roles without review, creating unmonitored escalation paths that bypass modern security controls.
MC-204: Lack of Privileged Access Governance
Insufficient review processes for hybrid privilege inheritance, allowing privilege drift and accumulation of unnecessary administrative access over time.
This breach pattern spans multiple stages of the identity-focused attack lifecycle, creating a complete path from initial compromise to cloud administrative takeover.
1
Stage 4
Authentication Abuse
Attacker compromises on-prem credentials or authentication mechanisms to establish initial hybrid identity foothold.
2
Stage 5
Privilege Escalation
Exploitation of sync paths and hybrid group memberships to elevate privileges from on-prem to cloud admin roles.
3
Stage 8
Persistence via Identity
Establishment of persistent access through hybrid service accounts and shadow admin creation that survives remediation.
4
Stage 9
Action on Objectives
Execution of primary mission goals using fully escalated cloud admin privileges, often resulting in data exfiltration or ransomware deployment.
Hybrid escalation frequently culminates in complete cloud admin takeover, granting attackers unrestricted access to all Entra ID resources and connected services.
Russian state-sponsored group extensively documented using hybrid escalation techniques in major government and enterprise breaches, targeting Azure AD sync infrastructure.
APT28 (ICTAM-002)
Military intelligence-linked threat actor specializing in AD-to-Entra privilege pivot operations, exploiting trust relationships in hybrid environments.
RaaS Affiliates (ICTAM-020)
Ransomware-as-a-Service operators weaponizing hybrid AD weaknesses to achieve rapid privilege escalation and maximize encryption impact across cloud resources.
Insider Threat Groups (ICTAM-025)
Malicious insiders and insider-enabled external actors abusing legitimate knowledge of hybrid privilege inheritance for unauthorized access escalation.