Detection rules › Splunk
Non Firefox Process Access Firefox Profile Dir
The following analytic detects non-Firefox processes accessing the Firefox profile directory, which contains sensitive user data such as login credentials, browsing history, and cookies. It leverages Windows Security Event logs, specifically event code 4663, to monitor access attempts. This activity is significant because it may indicate attempts by malware, such as RATs or trojans, to harvest user information. If confirmed malicious, this behavior could lead to data exfiltration, unauthorized access to user accounts, and further compromise of the affected system.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Credential Access | T1555.003 Credentials from Password Stores: Credentials from Web Browsers |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Security-Auditing | 4663 | An attempt was made to access an object. |
Stages and Predicates
Stage 1: search
search NOT ProcessName IN ("*\\explorer.exe", "*\\firefox.exe", "*sql*") EventCode=4663 ObjectName="*\\AppData\\Roaming\\Mozilla\\Firefox\\Profiles*"
Stage 2: stats
stats BY ObjectName, ObjectType, ProcessName, AccessMask, EventCode, dest
Stage 3: search
search
Stage 4: search
search
Stage 5: search
search `macro`
Exclusions
Top-level NOT(...) conjuncts — predicates this rule actively suppresses.
| Stage | Field | Kind | Excluded values |
|---|---|---|---|
| 1 | process_name | in | "*\\explorer.exe", "*\\firefox.exe", "*sql*" |
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
EventCode | eq |
|
ObjectName | eq |
|
Neighbors
Broader alternatives (more inclusive than this rule)
These rules match a superset of what this rule catches. They cover the same events plus more. Use them if you want wider coverage and can absorb more false positives.
- Windows Credential Access From Browser Password Store (drops 2 filters this rule applies)