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TECHNIQUES
PRE-ATT&CK
Priority Definition Planning
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Target Selection
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Event Triggered Execution
Hijack Execution Flow
Process Injection
Scheduled Task/Job
Valid Accounts
Defense Evasion
Abuse Elevation Control Mechanism
Access Token Manipulation
Execution Guardrails
File and Directory Permissions Modification
Hide Artifacts
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Impair Defenses
Indicator Removal on Host
Masquerading
Modify Authentication Process
Modify Cloud Compute Infrastructure
Obfuscated Files or Information
Pre-OS Boot
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Signed Binary Proxy Execution
Signed Script Proxy Execution
Subvert Trust Controls
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Trusted Developer Utilities Proxy Execution
Use Alternate Authentication Material
Valid Accounts
Virtualization/Sandbox Evasion
Credential Access
Brute Force
Credentials from Password Stores
Input Capture
Man-in-the-Middle
Modify Authentication Process
OS Credential Dumping
Steal or Forge Kerberos Tickets
Unsecured Credentials
Discovery
Account Discovery
Permission Groups Discovery
Software Discovery
Virtualization/Sandbox Evasion
Lateral Movement
Remote Service Session Hijacking
Remote Services
Use Alternate Authentication Material
Collection
Archive Collected Data
Data from Information Repositories
Data Staged
Email Collection
Input Capture
Man-in-the-Middle
Command and Control
Application Layer Protocol
Data Encoding
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Dynamic Resolution
Encrypted Channel
Proxy
Traffic Signaling
Web Service
Exfiltration
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Impact
Data Manipulation
Defacement
Disk Wipe
Endpoint Denial of Service
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Mobile
Initial Access
Execution
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Credential Access
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  1. Home
  2. Techniques
  3. Enterprise
  4. File and Directory Permissions Modification
  5. Windows File and Directory Permissions Modification

File and Directory Permissions Modification: Windows File and Directory Permissions Modification

ID Name
T1222.001 Windows File and Directory Permissions Modification
T1222.002 Linux and Mac File and Directory Permissions Modification

Adversaries may modify file or directory permissions/attributes to evade access control lists (ACLs) and access protected files.[1][2] 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.).

Windows implements file and directory ACLs as Discretionary Access Control Lists (DACLs).[3] Similar to a standard ACL, DACLs identifies the accounts that are allowed or denied access to a securable object. When an attempt is made to access a securable object, the system checks the access control entries in the DACL in order. If a matching entry is found, access to the object is granted. Otherwise, access is denied.[4]

Adversaries can interact with the DACLs using built-in Windows commands, such as icacls, takeown, and attrib, which can grant adversaries higher permissions on specific files and folders. Further, PowerShell provides cmdlets that can be used to retrieve or modify file and directory DACLs. 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, or tainting/hijacking other instrumental binary/configuration files via Hijack Execution Flow.

ID: T1222.001
Sub-technique of:  T1222
Tactic: Defense Evasion
Platforms: Windows
Permissions Required: Administrator, SYSTEM, User
Data Sources: File monitoring, Process command-line parameters, Process monitoring, Windows event logs
Version: 1.0
Created: 04 February 2020
Last Modified: 29 March 2020

Procedure Examples

Name Description
JPIN

JPIN can use the command-line utility cacls.exe to change file permissions.[5]
WannaCry

WannaCry uses attrib +h and icacls . /grant Everyone:F /T /C /Q to make some of its files hidden and grant all users full access controls.[6]

Mitigations

Mitigation Description
Privileged Account Management

Ensure critical system files as well as those known to be abused by adversaries have restrictive permissions and are owned by an appropriately privileged account, especially if access is not required by users nor will inhibit system functionality.
Restrict File and Directory Permissions

Applying more restrictive permissions to files and directories could prevent adversaries from modifying the access control lists.

Detection

Monitor and investigate attempts to modify DACLs and file/directory ownership. Many of the commands used to modify DACLs and file/directory ownership are built-in system utilities and may generate a high false positive alert rate, so compare against baseline knowledge for how systems are typically used and correlate modification events with other indications of malicious activity where possible.

Consider enabling file/directory permission change auditing on folders containing key binary/configuration files. For example, Windows Security Log events (Event ID 4670) are created when DACLs are modified.[7]

References

  1. Hybrid Analysis. (2018, June 12). c9b65b764985dfd7a11d3faf599c56b8.exe. Retrieved August 19, 2018.
  2. Hybrid Analysis. (2018, May 30). 2a8efbfadd798f6111340f7c1c956bee.dll. Retrieved August 19, 2018.
  3. Microsoft. (2018, May 30). DACLs and ACEs. Retrieved August 19, 2018.
  4. M. Satran, M. Jacobs. (2018, May 30). Access Control Lists. Retrieved February 4, 2020.
  1. Windows Defender Advanced Threat Hunting Team. (2016, April 29). PLATINUM: Targeted attacks in South and Southeast Asia. Retrieved February 15, 2018.
  2. Noerenberg, E., Costis, A., and Quist, N. (2017, May 16). A Technical Analysis of WannaCry Ransomware. Retrieved March 25, 2019.
  3. Netsurion. (2014, February 19). Monitoring File Permission Changes with the Windows Security Log. Retrieved August 19, 2018.