Detection rules › Splunk
Windows Raw Access To Master Boot Record Drive
The following analytic detects suspicious raw access reads to the drive containing the Master Boot Record (MBR). It leverages Sysmon EventCode 9 to identify processes attempting to read or write to the MBR sector, excluding legitimate system processes. This activity is significant because adversaries often target the MBR to wipe, encrypt, or overwrite it as part of their impact payload. If confirmed malicious, this could lead to system instability, data loss, or a complete system compromise, severely impacting the organization's operations.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Impact | T1561.002 Disk Wipe: Disk Structure Wipe |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Sysmon | 9 | RawAccessRead |
Stages and Predicates
Stage 1: search
search NOT Image IN ("*\\Windows\\SysWOW64\\*", "*\\Windows\\System32\\*") Device="\\\\Device\\\\Harddisk0\\\\DR0" EventCode=9
Stage 2: stats
stats BY dest, dvc, process_exec, process_guid, process_id, process_name, process_path, signature, signature_id, user_id, vendor_product, Device, Image
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 | Image | in | "*\\Windows\\SysWOW64\\*", "*\\Windows\\System32\\*" |
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 |
|---|---|---|
Device | eq |
|
EventCode | eq |
|