File and Directory Permissions Modification: Linux and Mac Permissions T1222.002
Tactic: 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.).
Events covered
2 catalog events are tagged with this technique by at least one rule.
| Provider | Event | Title |
|---|---|---|
| Linux-Auditd | Event ID 1309 | EXECVE |
| Sysmon-for-Linux | Event ID 1 | Process Create |
Authoring guide
Patterns shared across the 18 rules above: which fields they filter on, what specific values they look for, and what they exclude. The catalog normalizes field names across vendors so Sigma's Image, Elastic's process.name, and Splunk's process_name collapse into one row. Each rule contributes at most once per row.
Fields filtered most (22 distinct)
The fields most rules look at when detecting this technique. The How column shows the operators authors use (eq, wildcard, regex_match, match) and how often each appears. Sample values are concrete examples to start from, not an exhaustive list.
Top indicator values (168 distinct)
Specific (field, operator, value) combinations the rules check for, ranked by how many rules under this technique use each one. The Corpus reach column counts how many rules across the entire catalog (any technique) check the same combination. High numbers point to widely-used indicators that are likely noisy on their own; combine them with another condition for useful signal. Blank means the combination is specific to rules under this technique. Click a value to expand the rules under this technique that use it.
Exclusions (129 distinct)
Field/operator/value combinations excluded by rules under this technique (top-level not() clauses), sorted by how many rules exclude each. These are the false-positive paths the community has learned to filter out. A new rule that ignores the high-count entries here will likely fire on the same noisy paths. Click a value to expand the rules under this technique that exclude it.
Rules under this technique
Every rule in the catalog tagged with this technique, grouped by vendor. Click a rule title for its full predicates, exclusions, and indicators.
Sigma 4 rules
- Chmod Targeting Sensitive Directories
- File or Folder Permissions Change
- Remove Immutable File Attribute
- Remove Immutable File Attribute - Auditd
Elastic 10 rules
- Access Control List Modification via setfacl
- Executable Bit Set for Potential Persistence Script
- File Creation in World-Writable Directory by Unusual Process
- File Execution Permission Modification Detected via Defend for Containers
- File made Immutable by Chattr
- File Permission Modification in Writable Directory
- Potential Unauthorized Access via Wildcard Injection Detected
- Privilege Escalation via CAP_CHOWN/CAP_FOWNER Capabilities
- Suspicious File Made Executable via Chmod Inside A Container
- System Binary Path File Permission Modification