Techniques › T1542 › AN0774
AN0774 Analytic 0774
Windows · attack.mitre.org · ATT&CK Enterprise v19.2
<p>Unusual modification of boot records (MBR, VBR) or EFI partitions not associated with legitimate patch cycles or OS upgrades. Registry or WMI events associated with firmware update tools executed from unexpected parent processes. API calls (e.g., DeviceIoControl) writing directly to raw disk sectors. Subsequent abnormal boot configuration changes followed by unsigned driver loads.</p>
- Detects
- T1542 Pre-OS Boot
- Part of
- DET0278 Detection Strategy for T1542 Pre-OS Boot
Log sources and channels
Exactly as MITRE states them in x_mitre_log_source_references. Where a channel is vague, it is vague in the source; kevmap does not tidy it.
| Log source | Channel | Data component |
|---|---|---|
| WinEventLog:Security | EventCode=4688 | DC0032 Process Creation |
| WinEventLog:Sysmon | EventCode=11 | DC0039 File Creation |
| WinEventLog:Sysmon | EventCode=9 | DC0054 Drive Access |
Mutable elements
Parameters MITRE marks as environment-specific. These are the knobs you are expected to tune; they are why an analytic is not a rule.
| Field | Description |
|---|---|
AllowedFirmwareUpdateTools | Legitimate vendor tools or processes authorized to modify firmware or boot records. |
TimeWindow | Correlating boot-sector modification with subsequent reboot events. |
EntropyThreshold | Heuristic threshold for detecting obfuscated/packed boot code. |