T1027: Obfuscated Files or Information
AI Answer
Adversaries may attempt to make an executable or file difficult to discover or analyze by encrypting, encoding, or otherwise obfuscating its contents on the system or in transit. This is common behavior that can be used across different platforms and the network to evade defenses. Payloads may be compressed, archived, or encrypted in order to (Source: MITRE ATT&CK T1027)
ATT&CK Mapping
| Field | Value |
|---|---|
| Technique ID | T1027 |
| Name | Obfuscated Files or Information |
| Tactic | stealth (stealth) |
| Platforms | ESXi, Linux, macOS, Network Devices, Windows |
| Sub-technique | No |
Why it matters
In the OpenTrojan knowledge graph, Obfuscated Files or Information (T1027) is one of the highest-connectivity ATT&CK techniques: 160 MITRE STIX relationships reference this technique; 18 threat groups observed using it; 138 software families associated; 4 campaigns associated; 5 OpenTrojan content pages reference it. These counts are derived from MITRE ATT&CK STIX relationships and are not an estimate of exploitation volume.
How attackers use it
Behavior described below is from the MITRE ATT&CK canonical definition (source: https://attack.mitre.org/techniques/T1027). Adversaries may attempt to make an executable or file difficult to discover or analyze by encrypting, encoding, or otherwise obfuscating its contents on the system or in transit. This is common behavior that can be used across different platforms and the network to evade defenses. Payloads may be compressed, archived, or encrypted in order to avoid detection. These payloads may be used during Initial Access or later to mitigate detection. Sometimes a user’s action may be required to open and Deobfuscate/Decode Files or Information for User Execution. The user may also be required to input a password to open a password protected compressed/encrypted file that was provided by the adversary. Adversaries may also use compressed or archived scripts, such as JavaScript. Portions of files can also be encoded to hide the plain-text strings that would otherwise help defenders with discovery. Payloads may also be split into separate, seemingly benign files that only reveal malicious functionality when reassembled. Adversaries may also abuse Command Obfuscation to obscure commands executed from payloads or directly via Command and Scripting Interpreter. Environment variables, aliases, characters, and other platform/language specific semantics can be used to evade signature based detections and application control mechanisms.
Detection
DET0378 Behavioral Detection of Obfuscated Files or Information AN1064 Correlates script execution or suspicious parent processes with creation or modification of encoded, compressed, or encrypted file formats (e.g., .zip, .7z, .enc) and abnormal command-line syntax or PowerShell obfuscation. AN1065 Detects use of gzip, base64, tar, or openssl in scripts or commands that encode/encrypt files after file staging or system enumeration. AN1066 Monitors use of archive or encryption tools (zip, openssl) tied to user-scripted activity or binaries writing encoded payloads under /Users or /Volumes. AN1067 Identifies transfer of base64, uuencoded, or high-entropy files over HTTP, FTP, or custom protocols in lateral movement or exfiltration streams. AN1068 Detects encoded PowerCLI or Base64-encoded payloads staged via datastore uploads or shell access (e.g., ESXi Shell or backdoored VIBs).
Detection strategy text is from the MITRE ATT&CK official technique page (https://attack.mitre.org/techniques/T1027).
Mitigation
User Training involves educating employees and contractors on recognizing, reporting, and preventing cyber threats that rely on human interaction, such as phishing, social engineering, and other manipulative techniques. Comprehensive training programs create a human firewall by empowering users to be an active component of the organization’s cybersecurity defenses. This mitigation can be implemented through the following measures:
Create Comprehensive Training Programs:
- Design training modules tailored to the organization’s risk profile, covering topics such as phishing, password management, and incident reporting.
- Provide role-specific training for high-risk employees, such as helpdesk staff or executives.
Use Simulated Exercises:
- Conduct phishing simulations to measure user susceptibility and provide targeted follow-up training.
- Run social engineering drills to evaluate employee responses and reinforce protocols.
Leverage Gamification and Engagement:
- Introduce interactive learning methods such as quizzes, gamified challenges, and rewards for successful detection and reporting of threats.
Incorporate Security Policies into Onboarding:
- Include cybersecurity training as part of the onboarding process for new employees.
- Provide easy-to-understand materials outlining acceptable use policies and reporting procedures.
Regular Refresher Courses:
- Update training materials to include emerging threats and techniques used by adversaries.
- Ensure all employees complete periodic refresher courses to stay informed.
Emphasize Real-World Scenarios:
- Use case studies of recent attacks to demonstrate the consequences of successful phishing or social engineering.
- Discuss how specific employee actions can prevent or mitigate such attacks.
Mitigation guidance is from the MITRE ATT&CK course-of-action associated with this technique.
Related Software
- TrickBot
- EKANS
- SynAck
- Bumblebee
- BRICKSTORM
- Amadey
- Orz
- NOKKI
- AvosLocker
- COATHANGER
- Sardonic
- Matryoshka
Software associations are from MITRE ATT&CK STIX relationships (observed usage, not attribution).
Related Threat Groups
- GALLIUM
- APT3
- Kimsuky
- APT41
- Gamaredon Group
- Gallmaker
- Sandworm Team
- Mustang Panda
- Rocke
- APT37
- Ke3chang
- RedCurl
Group associations are from MITRE ATT&CK STIX relationships.
Related Campaigns
- 3CX Supply Chain Attack
- C0015
- 2016 Ukraine Electric Power Attack
- C0017
Campaign associations are from MITRE ATT&CK STIX relationships.
Related Content
- APT28 (Fancy Bear)
- APT29 (Cozy Bear / Midnight Blizzard)
- APT41 (Winnti)
- Cl0p (CLOP) Ransomware Group
- Scattered Spider (UNC3944)
References
- https://attack.mitre.org/techniques/T1027
- https://www.volexity.com/blog/2016/11/09/powerduke-post-election-spear-phishing-campaigns-targeting-think-tanks-and-ngos
- https://web.archive.org/web/20170923102302/https://www.fireeye.com/blog/threat-research/2017/06/obfuscation-in-the-wild.html
- https://www.blackhat.com/docs/us-17/thursday/us-17-Bohannon-Revoke-Obfuscation-PowerShell-Obfuscation-Detection-And%20Evasion-Using-Science-wp.pdf
- https://www.welivesecurity.com/2013/04/26/linuxcdorked-new-apache-backdoor-in-the-wild-serves-blackhole
- https://www.carbonblack.com/2016/09/23/security-advisory-variants-well-known-adware-families-discovered-include-sophisticated-obfuscation-techniques-previously-associated-nation-state-attacks
- https://researchcenter.paloaltonetworks.com/2017/03/unit42-pulling-back-the-curtains-on-encodedcommand-powershell-attacks
Source Attribution
Source: MITRE ATT&CK (MITRE ATT&CK) · Confidence: 0.9 · Reviewed: OpenTrojan - Human Review
Start Investigation
Move from reading to investigating T1027 Obfuscated Files or Information. The workspace is a structured analysis surface — not a chat — organised as:
- Question — what do you need to know about T1027 Obfuscated Files or Information?
- Evidence — assertions mapped to verifiable references.
- Timeline — events in chronological order.
- Related Entities — CVE, threat actor, campaign, malware links.
- Sources — NVD, CISA KEV, MITRE ATT&CK, vendor advisories.
- Notes — your own observations and working hypotheses.
AI assistance is limited to summarising, explaining, and suggesting related evidence. AI never completes your investigation, modifies entity relationships, or generates facts — all published analysis stays human-reviewed.