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ATT&CK Technique

File and Directory Permissions Modification

T1222 · defense-impairment

Adversaries may modify file or directory permissions/attributes to evade access control lists (ACLs) and access protected files. File and directory permissions are commonly managed by ACLs configured by the file or directory owner, or users with the appropriate permissions. File and directory ACL implementations vary by platform, but generally explicitly designate which users or groups can perform which actions (read, write, execute, etc.).

Modifications may include changing specific access rights, which may require taking ownership of a file or directory and/or elevated permissions depending on the file or directory’s existing permissions. This may enable malicious activity such as modifying, replacing, or deleting specific files or directories. Specific file and directory modifications may be a required step for many techniques, such as establishing Persistence via Accessibility Features, Boot or Logon Initialization Scripts, Unix Shell Configuration Modification, or tainting/hijacking other instrumental binary/configuration files via Hijack Execution Flow.

Adversaries may also change permissions of symbolic links. For example, malware (particularly ransomware) may modify symbolic links and associated settings to enable access to files from local shortcuts with remote paths.

ESXiLinuxmacOSWindows
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Actors Using This

1
chinaVolt Typhoon
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Atomic Tests

3
Executable Atomic Red Team test cases for exercising this technique in a lab. Copy a command, run it on the listed platform, confirm your detections fire.
command_promptelevatedwindowsEnable Local and Remote Symbolic Links via fsutil
Use fsutil to enable both ‘remote to local’ and ‘remote to remote’ symbolic links. This allows access to files from local shortcuts with local or remote paths. [reference](https://symantec-enterprise-blogs.security.com/threat-intelligence/noberus-blackcat-alphv-rust-ransomware/) 
fsutil behavior set SymlinkEvaluation R2L:1
fsutil behavior set SymlinkEvaluation R2R:1
command_promptelevatedwindowsEnable Local and Remote Symbolic Links via reg.exe
Use reg.exe to enable both ‘remote to local’ and ‘remote to remote’ symbolic links. This allows access to files from local shortcuts with local or remote paths. [reference](https://symantec-enterprise-blogs.security.com/threat-intelligence/noberus-blackcat-alphv-rust-ransomware/) 
reg add "HKLM\SYSTEM\CurrentControlSet\Control\FileSystem" /v SymlinkRemoteToLocalEvaluation /t REG_DWORD /d "1" /f
reg add "HKLM\SYSTEM\CurrentControlSet\Control\FileSystem" /v SymlinkRemoteToRemoteEvaluation /t REG_DWORD /d "1" /f
powershellelevatedwindowsEnable Local and Remote Symbolic Links via Powershell
Use Powershell to enable both ‘remote to local’ and ‘remote to remote’ symbolic links. This allows access to files from local shortcuts with local or remote paths. [reference](https://symantec-enterprise-blogs.security.com/threat-intelligence/noberus-blackcat-alphv-rust-ransomware/) 
New-ItemProperty -Path HKLM:\Software\Policies\Microsoft\Windows\Filesystems\NTFS -Name SymlinkRemoteToLocalEvaluation -PropertyType DWORD -Value 1 -Force -ErrorAction Ignore
New-ItemProperty -Path HKLM:\Software\Policies\Microsoft\Windows\Filesystems\NTFS -Name SymlinkRemoteToRemoteEvaluation -PropertyType DWORD -Value 1 -Force -ErrorAction Ignore
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Mitigations

2
MITRE ATT&CK mitigations - vendor-agnostic guidance for reducing exposure to this technique.
M1022Restrict File and Directory Permissions

Restricting file and directory permissions involves setting access controls at the file system level to limit which users, groups, or processes can read, write, or execute files. By configuring permissions appropriately, organizations can reduce the attack surface for adversaries seeking to access sensitive data, plant malicious code, or tamper with system files.

Enforce Least Privilege Permissions
  • Remove unnecessary write permissions on sensitive files and directories.
  • Use file ownership and groups to control access for specific roles. Example (Windows): Right-click the shared folder.
  • Properties.
  • Security tab.
  • Adjust permissions for NTFS ACLs.
Harden File Shares
  • Disable anonymous access to shared folders.
  • Enforce NTFS permissions for shared folders on Windows. Example: Set permissions to restrict write access to critical files, such as system executables (e.g., /bin or /sbin on Linux). Use tools like chown and chmod to assign file ownership and limit access. On Linux, apply: chmod 750 /etc/sensitive.conf `chown root:admin /etc/sensitive.
conf` File Integrity Monitoring (FIM)
  • Use tools like Tripwire, Wazuh, or OSSEC to monitor changes to critical file permissions.
Audit File System Access
  • Enable auditing to track permission changes or unauthorized access attempts.
  • Use auditd (Linux) or Event Viewer (Windows) to log activities.
Restrict Startup Directories
  • Configure permissions to prevent unauthorized writes to directories like C:\ProgramData\Microsoft\Windows\Start Menu. Example: Restrict write access to critical directories like /etc/, /usr/local/, and Windows directories such as C:\Windows\System32.
  • On Windows, use icacls to modify permissions: icacls "C:\Windows\System32" /inheritance:r /grant:r SYSTEM:(OI)(CI)F.
  • On Linux, monitor permissions using tools like lsattr or auditd.
M1026Privileged Account Management

Privileged Account Management focuses on implementing policies, controls, and tools to securely manage privileged accounts (e.g., SYSTEM, root, or administrative accounts). This includes restricting access, limiting the scope of permissions, monitoring privileged account usage, and ensuring accountability through logging and auditing.

Account Permissions and Roles
  • Implement RBAC and least privilege principles to allocate permissions securely.
  • Use tools like Active Directory Group Policies to enforce access restrictions.
Credential Security
  • Deploy password vaulting tools like CyberArk, HashiCorp Vault, or KeePass for secure storage and rotation of credentials.
  • Enforce password policies for complexity, uniqueness, and expiration using tools like Microsoft Group Policy Objects (GPO).
Multi-Factor Authentication (MFA)
  • Enforce MFA for all privileged accounts using Duo Security, Okta, or Microsoft Azure AD MFA.
Privileged Access Management (PAM)
  • Use PAM solutions like CyberArk, BeyondTrust, or Thycotic to manage, monitor, and audit privileged access.
Auditing and Monitoring
  • Integrate activity monitoring into your SIEM (e.g., Splunk or QRadar) to detect and alert on anomalous privileged account usage.
Just-In-Time Access
  • Deploy JIT solutions like Azure Privileged Identity Management (PIM) or configure ephemeral roles in AWS and GCP to grant time-limited elevated permissions.
Tools for Implementation Privileged Access Management (PAM)
  • CyberArk, BeyondTrust, Thycotic, HashiCorp Vault.
Credential Management
  • Microsoft LAPS (Local Admin Password Solution), Password Safe, HashiCorp Vault, KeePass.
Multi-Factor Authentication
  • Duo Security, Okta, Microsoft Azure MFA, Google Authenticator.
Linux Privilege Management
  • sudo configuration, SELinux, AppArmor.
Just-In-Time Access
  • Azure Privileged Identity Management (PIM), AWS IAM Roles with session constraints, GCP Identity-Aware Proxy.
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Detection Coverage

2/6 layers
Coverage across standard detection surfaces. Rows marked none have no rule of that type mapped. Some are real blind spots worth closing; others are simply not applicable to this technique (e.g. YARA matches malware files, not network behaviour).
Behavioral / log (Sigma) 2
Analytics (MITRE CAR) 1
Runtime / container (Falco) none
File / malware (YARA) none
Network (Suricata/Snort) none
Vuln scan (Nuclei) none
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CAR Analytics

1
MITRE Cyber Analytics Repository - field-tested detection logic for this technique, written as pseudocode/queries you adapt to your own SIEM (Splunk, Sentinel, EQL). Each is a ready starting point for a detection rule, not just a description.
CAR-2019-07-001Moderate coverageAccess Permission Modification

Adversaries sometimes modify object access rights at the operating system level.

There are varying motivations behind this action
  • they may not want some files/objects to be changed on systems for persistence reasons and therefore provide admin only rights; also, they may want files to be accessible with lower levels of permissions. Note.
  • this analytic references file permissions, which are not currently in the CAR data model.
Pseudocode - Windows - Pseudocode
log_name == "Security" AND
event_code == "4670" AND
object_type == "File" AND
subject_security_id != "NT AUTHORITY\SYSTEM"
Splunk - Windows - Splunk
index=__your_windows_security_log_index__ EventCode=4670 Object_Type="File" Security_ID!="NT AUTHORITY\\SYSTEM"
Pseudocode - Linux - Pseudocode
processes = search Process:Create
chmod_processes = filter processes where command_line == "chmod *"
output chmod_processes
LogPoint
norm_id=WindowsSysmon channel="Security" event_id=4670 object_type="File" -user_id="S-1-5-18"
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Comply & Defend

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