ATT&CK coverage › Technique
Deobfuscate/Decode Files or Information T1140
Adversaries may use Obfuscated Files or Information to hide artifacts of an intrusion from analysis. They may require separate mechanisms to decode or deobfuscate that information depending on how they intend to use it. Methods for doing that include built-in functionality of malware or by using utilities present on the system.
Events covered
8 catalog events are tagged with this technique by at least one rule.
Authoring guide
Patterns shared across the 25 rules above: which fields they filter on, what specific values they look for, and what they exclude. Field names are normalized 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 (109 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.
Common exclusions (9 distinct)
Field/operator/value combinations that rules under this technique routinely exclude (top-level not() clauses). 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.
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 8 rules
- Base64 Encoded PowerShell Command Detected
- DNS-over-HTTPS Enabled by Registry
- MSHTA Execution with Suspicious File Extensions
- Ping Hex IP
- Potential Commandline Obfuscation Using Escape Characters
- PowerShell Base64 Encoded FromBase64String Cmdlet
- PowerShell Decompress Commands
- Suspicious XOR Encoded PowerShell Command
Elastic 12 rules
- Dynamic IEX Reconstruction via Method String Access
- Potential Dynamic IEX Reconstruction via Environment Variables
- Potential PowerShell Obfuscation via Backtick-Escaped Variable Expansion
- Potential PowerShell Obfuscation via Character Array Reconstruction
- Potential PowerShell Obfuscation via Concatenated Dynamic Command Invocation
- Potential PowerShell Obfuscation via High Numeric Character Proportion
- Potential PowerShell Obfuscation via Invalid Escape Sequences
- Potential PowerShell Obfuscation via Reverse Keywords
- Potential PowerShell Obfuscation via Special Character Overuse
- Potential PowerShell Obfuscation via String Concatenation
- Potential PowerShell Obfuscation via String Reordering
- PowerShell Obfuscation via Negative Index String Reversal