T1556: Modify Authentication Process
Adversaries may modify authentication mechanisms and processes to access user credentials or enable otherwise unwarranted access to accounts. The authentication process is handled by mechanisms, such as the Local Security Authentication Server (LSASS) process and the Security Accounts Manager (SAM) on Windows, pluggable authentication modules (PAM) on Unix-based systems, and authorization plugins on MacOS systems, responsible for gathering, storing, and validating credentials. By modifying an authentication process, an adversary may be able to authenticate to a service or system without using Valid Accounts.
Adversaries may maliciously modify a part of this process to either reveal credentials or bypass authentication mechanisms. Compromised credentials or access may be used to bypass access controls placed on various resources on systems within the network and may even be used for persistent access to remote systems and externally available services, such as VPNs, Outlook Web Access and remote desktop.
Analyst context for executives and security teams
Modify Authentication Process matters because it targets the trust layer that decides who is allowed in. If an adversary can alter authentication components, they may capture credentials, bypass normal login controls, or preserve access without relying on ordinary valid account use. For leaders, this is an identity resilience issue across Windows, Linux, macOS, network devices, SaaS, IaaS, office suites, and identity providers—not just an endpoint hardening concern.
Executive priority
Prioritize this technique where authentication systems are business-critical: domain controllers, identity providers, VPN or remote access paths, cloud identity integrations, network devices, and externally reachable services. The key executive question is whether the organization can prove authentication mechanisms are hardened, monitored for unauthorized change, and recoverable during an incident. This also supports audit and compliance evidence because mitigations include account management, privileged account management, MFA, permission restriction, OS configuration, and auditing.
Technical view
ATT&CK maps T1556 to defense impairment, persistence, and credential access. SOC, detection engineering, and IR teams should validate monitoring for unauthorized changes to authentication components across the supported platforms. Relationship context shows sub-techniques for Windows domain controller authentication, password filter DLLs, network provider DLLs, reversible encryption, Linux/macOS PAM, network device authentication, MFA modification, hybrid identity, and conditional access policy modification. Because official detection text is not provided, teams should use DET0104, Detect Modification of Authentication Processes Across Platforms, as the ATT&CK-linked detection strategy and test coverage against local authentication architectures.
Likely telemetry
- Windows security and system events related to authentication configuration, privileged process changes, registry changes, password filter DLLs, network provider DLLs, LSASS/SAM-adjacent activity, and domain controller configuration changes
- Linux and macOS file integrity, package/configuration, and authentication logs covering PAM files, shared libraries, authorization plugins, and SSH-related authentication components
- Identity provider, IaaS, SaaS, and office suite audit logs for MFA settings, conditional access policy changes, hybrid identity configuration changes, and privileged identity administration
- Network device configuration, firmware or system image integrity evidence, authentication configuration changes, and administrative access logs
- Privileged account activity logs showing who changed authentication controls, when, from where, and through which administrative path
Detection direction
- Confirm that changes to authentication mechanisms generate alertable events, not just audit records retained for later review.
- Tune detections around high-risk change points: domain controllers, identity providers, hybrid identity synchronization paths, MFA and conditional access controls, PAM configuration, authentication DLL registration, and network device authentication images or settings.
- Correlate authentication-process changes with privileged account activity, new persistence indicators, unusual remote access success, and credential-access alerts.
- Account for legitimate administrative maintenance, OS upgrades, identity policy changes, and network device patching as common false-positive sources; require change-ticket or approved-administrator context where available.
- Treat absence of official ATT&CK detection text as a coverage gap to validate through local engineering and ATT&CK detection strategy DET0104 rather than assuming tool coverage.
Mitigation priorities
- Start with auditing: maintain evidence of authentication configuration baselines and review changes on all critical systems and identity platforms.
- Restrict file, directory, and registry permissions around authentication components so only authorized administrative paths can modify them.
- Strengthen privileged account and user account management with least privilege, lifecycle controls, and accountability for administrative changes.
- Apply privileged process integrity and operating system configuration hardening where supported to reduce tampering with authentication-related processes and services.
- Use MFA and strong password policies, while also monitoring for changes to MFA, reversible encryption, and conditional access controls because this technique can target those defenses directly.
Analyst notes and limits
The relationship set broadens the practical scope from host authentication to identity-provider and cloud-connected authentication controls. ATT&CK also relates this technique to ArcaneDoor, FIN13, Ebury, Kessel, and SILENTTRINITY, indicating that multiple campaign, group, and software entries have used or are mapped to this behavior; this should inform threat-informed validation without implying current exposure in any specific environment.
Official detection text for T1556 is not provided. The supplied data identifies platforms, tactics, mitigations, a detection strategy relationship, and sub-technique context, but local architecture determines which authentication components exist and which telemetry is available. This take does not assert active exploitation, customer impact, or guaranteed detection coverage.
Modify Authentication Process
Adversaries may modify authentication mechanisms and processes to access user credentials or enable otherwise unwarranted access to accounts. The authentication process is handled by mechanisms, such as the Local Security Authentication Server (LSASS) process and the Security Accounts Manager (SAM) on Windows, pluggable authentication modules (PAM) on Unix-based systems, and authorization plugins on MacOS systems, responsible for gathering, storing, and validating credentials. By modifying an authentication process, an adversary may be able to authenticate to a service or system without using Valid Accounts.
Adversaries may maliciously modify a part of this process to either reveal credentials or bypass authentication mechanisms. Compromised credentials or access may be used to bypass access controls placed on various resources on systems within the network and may even be used for persistent access to remote systems and externally available services, such as VPNs, Outlook Web Access and remote desktop.
How security teams should use this page
Treat this object as behavior context, not an attribution claim. Validate the related groups, software, data sources, and mitigations against official ATT&CK relationships and your own telemetry before making control-coverage decisions.
Related techniques
This mirrors the MITRE pattern of making group, software, campaign, and technique relationships scannable. Relationship notes come from mirrored ATT&CK relationship text when available.
| Domain | ID | Name | Relationship / procedure |
|---|---|---|---|
| Enterprise | T1556.004 | Network Device Authentication Sub-technique | Network Device Authentication subtechnique of this object. |
| Enterprise | T1556.001 | Domain Controller Authentication Sub-technique | Domain Controller Authentication subtechnique of this object. |
| Enterprise | T1556.009 | Conditional Access Policies Sub-technique | Conditional Access Policies subtechnique of this object. |
| Enterprise | T1556.008 | Network Provider DLL Sub-technique | Network Provider DLL subtechnique of this object. |
| Enterprise | T1556.002 | Password Filter DLL Sub-technique | Password Filter DLL subtechnique of this object. |
| Enterprise | T1556.006 | Multi-Factor Authentication Sub-technique | Multi-Factor Authentication subtechnique of this object. |
| Enterprise | T1556.007 | Hybrid Identity Sub-technique | Hybrid Identity subtechnique of this object. |
| Enterprise | T1556.005 | Reversible Encryption Sub-technique | Reversible Encryption subtechnique of this object. |
| Enterprise | T1556.003 | Pluggable Authentication Modules Sub-technique | Pluggable Authentication Modules subtechnique of this object. |
Groups, software, and campaigns
G1016: FIN13
S0377: Ebury
Ebury is an OpenSSH backdoor and credential stealer targeting Linux servers and container hosts developed by Windigo. Ebury is primarily installed through modifying shared libraries (`.so` files) executed by the legitimate OpenSSH program. First seen in 2009, Ebury has been used to maintain a botnet of servers, deploy additional malware, and steal cryptocurrency wallets, credentials, and credit card details.[1][2][3][4]
S0692: SILENTTRINITY
SILENTTRINITY is an open source remote administration and post-exploitation framework primarily written in Python that includes stagers written in Powershell, C, and Boo. SILENTTRINITY was used in a 2019 campaign against Croatian government agencies by unidentified cyber actors.[1][2]
S0487: Kessel
S9013: DRYHOOK
C0046: ArcaneDoor
ArcaneDoor is a campaign targeting networking devices from Cisco and other vendors between July 2023 and April 2024, primarily focused on government and critical infrastructure networks. ArcaneDoor is associated with the deployment of the custom backdoors Line Runner and Line Dancer. ArcaneDoor is attributed to a group referred to as UAT4356 or STORM-1849, and is assessed to be a state-sponsored campaign.[1][2]
All related ATT&CK context
Mitigation direction
Object version and sync metadata
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Imported snapshots across ATT&CK releases (1)
| Release | Bundle imported | Object version | Modified | Status | Raw hash |
|---|---|---|---|---|---|
| 19.1 | 3.0 | Current bundle | cebad3044733… |
Mirrored ATT&CK source object
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External references and citations
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[1]
mitre-attack T1556Open source URL
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