Data Encrypted for Impact T1486
Adversaries may encrypt data on target systems or on large numbers of systems in a network to interrupt availability to system and network resources. They can attempt to render stored data inaccessible by encrypting files or data on local and remote drives and withholding access to a decryption key. This may be done in order to extract monetary compensation from a victim in exchange for decryption or a decryption key (ransomware) or to render data permanently inaccessible in cases where the key is not saved or transmitted.
Events covered
13 catalog events are tagged with this technique by at least one rule.
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 1 | Process creation |
| Sysmon | Event ID 3 | Network connection |
| Sysmon | Event ID 5 | Process terminated |
| Sysmon | Event ID 7 | Image loaded |
| Sysmon | Event ID 11 | FileCreate |
| Security-Auditing | Event ID 4656 | A handle to an object was requested. |
| Security-Auditing | Event ID 4663 | An attempt was made to access an object. |
| Security-Auditing | Event ID 4688 | A new process has been created. |
| Security-Auditing | Event ID 5145 | A network share object was checked to see whether client can be granted desired access. |
| Defender-DeviceFileEvents | FileCreated | File created |
| Defender-DeviceInfo | any | Device inventory snapshot |
| PowerShell | Event ID 4103 | Payload Context: ContextInfo User Data: UserData. |
| PowerShell | Event ID 4104 | Creating Scriptblock text (MessageNumber of MessageTotal). |
Authoring guide
Patterns shared across the 28 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 (33 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 (192 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 (37 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 13 rules
- BitLocker feature configuration (Reg via command)
- BitLocker server feature activation (PowerShell)
- BlueSky Ransomware Artefacts
- FunkLocker Ransomware File Creation
- Load Of RstrtMgr.DLL By A Suspicious Process
- Load Of RstrtMgr.DLL By An Uncommon Process
- LockerGoga Ransomware Activity
- Portable Gpg.EXE Execution
- Potential Conti Ransomware Activity
- Renamed Gpg.EXE Execution
- Suspicious Creation TXT File in User Desktop
- Suspicious Reg Add BitLocker
- WannaCry Ransomware Activity
Elastic 3 rules
- Potential Ransomware Behavior - Note Files by System
- Potential Ransomware Note File Dropped via SMB
- Suspicious File Renamed via SMB
Splunk 7 rules
- High Process Termination Frequency
- Ransomware Notes bulk creation
- Ryuk Test Files Detected
- Samsam Test File Write
- Windows .Key File Creation in Root Directory
- Windows BitLocker Suspicious Command Usage
- Windows DiskCryptor Usage