T1027 — Obfuscated Files or Information

# T1027 - Obfuscated Files or Information

## SOC Recommendation
Investigate Obfuscated Files or Information activity in the context of Stealth: confirm scope, affected host/identity, and whether it matches expected administrative behaviour before deciding this is benign.

## D3FEND Mappings
| D3FEND Technique | Relationship | Practical SOC Action |
|---|---|---|
| File Analysis | Detect | Monitor for File Analysis indicators relevant to this technique. |
| File Encryption | Harden | Apply File Encryption to reduce this technique's viability before an incident occurs. |
| File Eviction | Evict | Use File Eviction to remove the adversary's foothold once this technique is confirmed. |
| Content Filtering | Isolate | Apply Content Filtering to contain the blast radius once this technique is observed. |

## Investigation Steps
1. Review Defender for Endpoint / Defender XDR alerts and timeline for the affected host or identity.
2. Check Sentinel analytics rules and incidents correlated with this technique.
3. Review Entra ID sign-in and audit logs if the technique involves an identity or cloud resource.

## Evidence to Collect
- Host or resource affected
- Account or identity involved
- Timestamp of the activity
- Related process, file, or network artifact
- Any preceding or follow-on alerts

## Response Actions
| Action | Risk | Automation Safe | Approval Required |
|---|---|---|---|
| Contain the affected host or account | Medium | No | Yes |
| Collect and preserve evidence | Low | Yes | No |

## KQL
```kql
// High Severity - Attack Surface - Misconfiguration Detected
let timeFrame = 5m;
CyfirmaASConfigurationAlerts_CL
| where severity == 'Critical' and TimeGenerated between (ago(timeFrame) .. now())
| extend
    Description=description,
    FirstSeen=first_seen,
    LastSeen=last_seen,
    RiskScore=risk_score,
    Domain=sub_domain,
    TopDomain=top_domain,
    NetworkIP=ip,
    AlertUID=alert_uid,
    UID=uid,
    Softwares=software,
    WebAppFirewall=web_app_firewall,
    ClickJackingDefence=click_jacking_defence,
    ContentSecurityPolicy=content_security_policy,
    CookieXssProtection=cookie_xss_protection,
    DataInjectionDefence=data_injection_defence,
    DomainStatus=domain_status,
    MissingEPPCodes=missing_epp_codes,
    SecureCookie=secure_cookie,
    SetCookieHttpsOnly=set_cookie_https_only,
    XFrameOptions=x_frame_options,
    X_XssProtection=x_xss_protection,
    ProviderName='CYFIRMA',
    ProductName='DeCYFIR/DeTCT'
| project
    TimeGenerated,
    Description,
    Domain,
    TopDomain,
    RiskScore,
    FirstSeen,
    LastSeen,
    NetworkIP,
    AlertUID,
    UID,
    Softwares,
    WebAppFirewall,
    ClickJackingDefence,
    ContentSecurityPolicy,
    CookieXssProtection,
    DataInjectionDefence,
    DomainStatus,
    MissingEPPCodes,
    SecureCookie,
    SetCookieHttpsOnly,
    XFrameOptions,
    X_XssProtection,
    ProviderName,
    ProductName
```
```kql
// File Hash Indicators with Block Action
let timeFrame = 5m;
CyfirmaIndicators_CL 
| where ConfidenceScore >= 80
    and TimeGenerated between (ago(timeFrame) .. now())
    and pattern contains 'file:hashes' and RecommendedActions has 'Block' and (isempty(Roles) or not(Roles has_any ('Malware', 'Trojan')))
| extend MD5 = extract(@"file:hashes\.md5\s*=\s*'([a-fA-F0-9]{32})'", 1, pattern)
| extend SHA1 = extract(@"file:hashes\.'SHA-1'\s*=\s*'([a-fA-F0-9]{40})'", 1, pattern)
| extend SHA256 = extract(@"file:hashes\.'SHA-256'\s*=\s*'([a-fA-F0-9]{64})'", 1, pattern)
| extend
    Algo_MD5='MD5',
    Algo_SHA1= 'SHA1',
    Algo_SHA256='SHA256',
    ProviderName = 'CYFIRMA',
    ProductName = 'DeCYFIR/DeTCT'
| project  
    MD5,
    SHA1,
    SHA256,
    Algo_MD5,
    Algo_SHA1,
    Algo_SHA256,
    ThreatActors,
    Sources,
    RecommendedActions,
    Roles,
    Country,
    name,
    Description,
    ConfidenceScore,
    SecurityVendors,
    IndicatorID,
    created,
    modified,
    valid_from,
    Tags,
    ThreatType,
    TimeGenerated,
    ProductName,
    ProviderName
```
```kql
// File Hash Indicators with Monitor Action
let timeFrame = 5m;
CyfirmaIndicators_CL 
| where ConfidenceScore >= 80
    and TimeGenerated between (ago(timeFrame) .. now())
    and pattern contains 'file:hashes' and RecommendedActions has 'Monitor' and (isempty(Roles) or not(Roles has_any ('Malware', 'Trojan')))
| extend MD5 = extract(@"file:hashes\.md5\s*=\s*'([a-fA-F0-9]{32})'", 1, pattern)
| extend SHA1 = extract(@"file:hashes\.'SHA-1'\s*=\s*'([a-fA-F0-9]{40})'", 1, pattern)
| extend SHA256 = extract(@"file:hashes\.'SHA-256'\s*=\s*'([a-fA-F0-9]{64})'", 1, pattern)
| extend
    Algo_MD5='MD5',
    Algo_SHA1= 'SHA1',
    Algo_SHA256='SHA256',
    ProviderName = 'CYFIRMA',
    ProductName = 'DeCYFIR/DeTCT'
| project  
    MD5,
    SHA1,
    SHA256,
    Algo_MD5,
    Algo_SHA1,
    Algo_SHA256,
    ThreatActors,
    Sources,
    RecommendedActions,
    Roles,
    Country,
    name,
    Description,
    ConfidenceScore,
    SecurityVendors,
    IndicatorID,
    created,
    modified,
    valid_from,
    Tags,
    ThreatType,
    TimeGenerated,
    ProductName,
    ProviderName
```

## Escalation Criteria
- Obfuscated Files or Information activity observed on a privileged account or critical system.
- Activity follows or precedes other suspicious behaviour in the same investigation.
- Automated triage cannot confidently rule out malicious intent.

## False Positive Considerations
- Legitimate administrative or maintenance activity matching this pattern.
- Approved security testing or red team exercise.
- Known benign software producing similar telemetry.

Generated by SOC Response Atlas by Basyrix.

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• /api/techniques/T1027.json
• /api/recommendations/T1027.json
• /api/d3fend/T1027.json
• /api/mappings/T1027.json
• /api/confluence/T1027.md

Example curl:

curl https://atlas.basyrix.com/api/recommendations/T1027.json

Response:

{
  "technique_id": "T1027",
  "name": "Obfuscated Files or Information",
  "priority": "high",
  "status": "draft",
  "version": "0.1.0",
  "last_reviewed": "2026-07-23",
  "generated_by": "SOC Response Atlas by Basyrix",
  "tactics": [
    "Stealth"
  ],
  "platforms": [
    "ESXi",
    "Linux",
    "macOS",
    "Network Devices",
    "Windows"
  ],
  "summary": "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...",
  "soc_recommendation": "Investigate Obfuscated Files or Information activity in the context of Stealth: confirm scope, affected host/identity, and whether it matches expected administrative behaviour before deciding this is benign.",
  "d3fend_mappings": [
    {
      "id": "D3-FA",
      "name": "File Analysis",
      "relationship": "detect",
      "practical_action": "Monitor for File Analysis indicators relevant to this technique.",
      "tooling": [
        "Defender for Endpoint"
      ]
    },
    {
      "id": "D3-FE",
      "name": "File Encryption",
      "relationship": "harden",
      "practical_action": "Apply File Encryption to reduce this technique's viability before an incident occurs.",
      "tooling": [
        "Defender for Endpoint"
      ]
    },
    {
      "id": "D3-FEV",
      "name": "File Eviction",
      "relationship": "evict",
      "practical_action": "Use File Eviction to remove the adversary's foothold once this technique is confirmed.",
      "tooling": [
        "Defender for Endpoint"
      ]
    },
    {
      "id": "D3-CF",
      "name": "Content Filtering",
      "relationship": "isolate",
      "practical_action": "Apply Content Filtering to contain the blast radius once this technique is observed.",
      "tooling": [
        "Defender for Endpoint"
      ]
    }
  ],
  "investigation_steps": {
    "microsoft": [
      "Review Defender for Endpoint / Defender XDR alerts and timeline for the affected host or identity.",
      "Check Sentinel analytics rules and incidents correlated with this technique.",
      "Review Entra ID sign-in and audit logs if the technique involves an identity or cloud resource."
    ],
    "generic": [
      "Confirm whether the observed obfuscated files or information activity matches expected administrative or application behaviour.",
      "Identify the host, account, or resource where the activity occurred and its business criticality.",
      "Check for related alerts before and after this activity to reconstruct the broader intrusion timeline.",
      "Real detection reference: \"CYFIRMA - Attack Surface - Configuration High Rule\" -- This alert is generated when CYFIRMA detects a critical misconfiguration in a public-facing asset or service. Such misconfigurations may include exposed admin interfaces, default credentials, open directory listings, or insecure protocols, which significantly increase the attack surface.\""
    ]
  },
  "evidence_to_collect": [
    "Host or resource affected",
    "Account or identity involved",
    "Timestamp of the activity",
    "Related process, file, or network artifact",
    "Any preceding or follow-on alerts"
  ],
  "response_actions": [
    {
      "name": "Contain the affected host or account",
      "category": "Containment",
      "risk": "Medium",
      "automation_safe": false,
      "approval_required": true,
      "tool": "Defender for Endpoint / Entra ID",
      "notes": "Requires approval -- confirm malicious intent before isolating a host or disabling an account."
    },
    {
      "name": "Collect and preserve evidence",
      "category": "Investigation",
      "risk": "Low",
      "automation_safe": true,
      "approval_required": false,
      "tool": "Defender for Endpoint",
      "notes": "Safe -- read-only evidence collection."
    }
  ],
  "queries": {
    "kql": [
      {
        "name": "30206b45-75d2-4c6a-87c5-f0861c1f2870 — CYFIRMA - Attack Surface - Configuration High Rule",
        "description": "This alert is generated when CYFIRMA detects a critical misconfiguration in a public-facing asset or service. Such misconfigurations may include exposed admin interfaces, default credentials, open directory listings, or insecure protocols, which significantly increase the attack surface.\" (Source: Microsoft's official Azure-Sentinel Detections (MIT licensed).)",
        "query": "// High Severity - Attack Surface - Misconfiguration Detected\nlet timeFrame = 5m;\nCyfirmaASConfigurationAlerts_CL\n| where severity == 'Critical' and TimeGenerated between (ago(timeFrame) .. now())\n| extend\n    Description=description,\n    FirstSeen=first_seen,\n    LastSeen=last_seen,\n    RiskScore=risk_score,\n    Domain=sub_domain,\n    TopDomain=top_domain,\n    NetworkIP=ip,\n    AlertUID=alert_uid,\n    UID=uid,\n    Softwares=software,\n    WebAppFirewall=web_app_firewall,\n    ClickJackingDefence=click_jacking_defence,\n    ContentSecurityPolicy=content_security_policy,\n    CookieXssProtection=cookie_xss_protection,\n    DataInjectionDefence=data_injection_defence,\n    DomainStatus=domain_status,\n    MissingEPPCodes=missing_epp_codes,\n    SecureCookie=secure_cookie,\n    SetCookieHttpsOnly=set_cookie_https_only,\n    XFrameOptions=x_frame_options,\n    X_XssProtection=x_xss_protection,\n    ProviderName='CYFIRMA',\n    ProductName='DeCYFIR/DeTCT'\n| project\n    TimeGenerated,\n    Description,\n    Domain,\n    TopDomain,\n    RiskScore,\n    FirstSeen,\n    LastSeen,\n    NetworkIP,\n    AlertUID,\n    UID,\n    Softwares,\n    WebAppFirewall,\n    ClickJackingDefence,\n    ContentSecurityPolicy,\n    CookieXssProtection,\n    DataInjectionDefence,\n    DomainStatus,\n    MissingEPPCodes,\n    SecureCookie,\n    SetCookieHttpsOnly,\n    XFrameOptions,\n    X_XssProtection,\n    ProviderName,\n    ProductName"
      },
      {
        "name": "7cb829b2-915a-42c2-adb9-725e9ce9bf43 — CYFIRMA - High severity File Hash Indicators with Block Action Rule",
        "description": "\"This query retrieves file hash indicators marked for blocking, with no assigned role, from the CyfirmaIndicators_CL table. It extracts MD5, SHA1, and SHA256 hashes and includes threat metadata for use in preventive security controls such as EDRs, threat intel platforms, or automated blocklists.\" (Source: Microsoft's official Azure-Sentinel Detections (MIT licensed).)",
        "query": "// File Hash Indicators with Block Action\nlet timeFrame = 5m;\nCyfirmaIndicators_CL \n| where ConfidenceScore >= 80\n    and TimeGenerated between (ago(timeFrame) .. now())\n    and pattern contains 'file:hashes' and RecommendedActions has 'Block' and (isempty(Roles) or not(Roles has_any ('Malware', 'Trojan')))\n| extend MD5 = extract(@\"file:hashes\\.md5\\s*=\\s*'([a-fA-F0-9]{32})'\", 1, pattern)\n| extend SHA1 = extract(@\"file:hashes\\.'SHA-1'\\s*=\\s*'([a-fA-F0-9]{40})'\", 1, pattern)\n| extend SHA256 = extract(@\"file:hashes\\.'SHA-256'\\s*=\\s*'([a-fA-F0-9]{64})'\", 1, pattern)\n| extend\n    Algo_MD5='MD5',\n    Algo_SHA1= 'SHA1',\n    Algo_SHA256='SHA256',\n    ProviderName = 'CYFIRMA',\n    ProductName = 'DeCYFIR/DeTCT'\n| project  \n    MD5,\n    SHA1,\n    SHA256,\n    Algo_MD5,\n    Algo_SHA1,\n    Algo_SHA256,\n    ThreatActors,\n    Sources,\n    RecommendedActions,\n    Roles,\n    Country,\n    name,\n    Description,\n    ConfidenceScore,\n    SecurityVendors,\n    IndicatorID,\n    created,\n    modified,\n    valid_from,\n    Tags,\n    ThreatType,\n    TimeGenerated,\n    ProductName,\n    ProviderName"
      },
      {
        "name": "952b7d77-a848-4888-a638-62fe877eb55d — CYFIRMA - High severity File Hash Indicators with Monitor Action Rule",
        "description": "\"This query retrieves file hash indicators marked for Monitoring, with no assigned role, from the CyfirmaIndicators_CL table. It extracts MD5, SHA1, and SHA256 hashes and includes threat metadata for use in preventive security controls such as EDRs, threat intel platforms.\" (Source: Microsoft's official Azure-Sentinel Detections (MIT licensed).)",
        "query": "// File Hash Indicators with Monitor Action\nlet timeFrame = 5m;\nCyfirmaIndicators_CL \n| where ConfidenceScore >= 80\n    and TimeGenerated between (ago(timeFrame) .. now())\n    and pattern contains 'file:hashes' and RecommendedActions has 'Monitor' and (isempty(Roles) or not(Roles has_any ('Malware', 'Trojan')))\n| extend MD5 = extract(@\"file:hashes\\.md5\\s*=\\s*'([a-fA-F0-9]{32})'\", 1, pattern)\n| extend SHA1 = extract(@\"file:hashes\\.'SHA-1'\\s*=\\s*'([a-fA-F0-9]{40})'\", 1, pattern)\n| extend SHA256 = extract(@\"file:hashes\\.'SHA-256'\\s*=\\s*'([a-fA-F0-9]{64})'\", 1, pattern)\n| extend\n    Algo_MD5='MD5',\n    Algo_SHA1= 'SHA1',\n    Algo_SHA256='SHA256',\n    ProviderName = 'CYFIRMA',\n    ProductName = 'DeCYFIR/DeTCT'\n| project  \n    MD5,\n    SHA1,\n    SHA256,\n    Algo_MD5,\n    Algo_SHA1,\n    Algo_SHA256,\n    ThreatActors,\n    Sources,\n    RecommendedActions,\n    Roles,\n    Country,\n    name,\n    Description,\n    ConfidenceScore,\n    SecurityVendors,\n    IndicatorID,\n    created,\n    modified,\n    valid_from,\n    Tags,\n    ThreatType,\n    TimeGenerated,\n    ProductName,\n    ProviderName"
      }
    ],
    "spl": [],
    "esql": [
      {
        "name": "74d31cb7-4a2c-44fe-9d1d-f375b9f3cb61 — Long Base64 Encoded Command via Scripting Interpreter",
        "description": "(ESQL) Identifies oversized command lines used by Python, PowerShell, Node.js, or Deno that contain base64 decoding or encoded-command patterns. Adversaries may embed long inline encoded payloads in scripting interpreters to evade inspection and execute malicious content across Windows, macOS, and Linux systems. (Source: Elastic's official detection-rules repository (Elastic License v2).)",
        "query": "FROM logs-endpoint.events.process-* METADATA _id, _index, _version, _ignored\n| MV_EXPAND _ignored\n| WHERE _ignored == \"process.command_line\"\n| WHERE event.category == \"process\" and event.type == \"start\"\n| EVAL command_line = TO_LOWER(process.command_line.text), pname = TO_LOWER(process.name)\n| WHERE \n(\n    (\n        /* Python: inline exec with base64 decode or -c flag with encoded payload */\n        pname like \"python*\" and\n        (\n            command_line like \"*b64decode*\" or\n            (command_line like \"*-c*\" and command_line like \"*base64*\")\n        )\n    ) or\n    (\n        /* PowerShell: encoded command flag — require trailing space to avoid matching\n           -Encoding, -EncryptionType, -EncryptionProvider, etc. */\n        (pname like \"powershell*\" or pname like \"pwsh*\") and\n        (\n            command_line rlike \".* -(e|en|enc|enco|encod|encode|encoded|encodedcommand) .+\" or\n            command_line like \"*-encodedcommand*\" or\n            command_line like \"*frombase64string*\"\n        )\n    ) or\n    (\n        /* Node.js: buffer.from must be paired with base64 to avoid matching\n           general Buffer usage; atob is always base64 */\n        pname like \"node*\" and\n        (\n            (command_line like \"*buffer.from*\" and command_line like \"*base64*\") or\n            command_line like \"*atob(*\"\n        )\n    ) or\n    (\n        /* Deno: eval( (not eval/evaluate/evaluation), atob, or buffer+base64 */\n        pname like \"deno*\" and\n        (\n            command_line like \"*atob(*\" or\n            (command_line like \"*buffer.from*\" and command_line like \"*base64*\") or\n            command_line like \"*eval(*\"\n        )\n    )\n)\n| EVAL Esql.length_cmdline = LENGTH(command_line)\n| WHERE Esql.length_cmdline >= 4000\n| KEEP *"
      },
      {
        "name": "d43f2b43-02a1-4219-8ce9-10929a32a618 — Potential PowerShell Obfuscation via Backtick-Escaped Variable Expansion",
        "description": "(ESQL) Detects PowerShell scripts that use backtick-escaped characters inside `${}` variable expansion (multiple backticks between word characters) to reconstruct strings at runtime. Attackers use variable-expansion obfuscation to split keywords, hide commands, and evade static analysis and AMSI. (Source: Elastic's official detection-rules repository (Elastic License v2).)",
        "query": "from logs-windows.powershell_operational* metadata _id, _version, _index\n| where event.code == \"4104\"\n\n// Filter out smaller scripts that are unlikely to implement obfuscation using the patterns we are looking for\n| eval Esql.script_block_length = length(powershell.file.script_block_text)\n| where Esql.script_block_length > 500\n\n// replace the patterns we are looking for with the 🔥 emoji to enable counting them\n// The emoji is used because it's unlikely to appear in scripts and has a consistent character length of 1\n| eval Esql.script_block_tmp = replace(powershell.file.script_block_text, \"\"\"\\$\\{(\\w++`){2,}\\w++\\}\"\"\", \"🔥\")\n\n// count how many patterns were detected by calculating the number of 🔥 characters inserted\n| eval Esql.script_block_pattern_count = length(Esql.script_block_tmp) - length(replace(Esql.script_block_tmp, \"🔥\", \"\"))\n\n// keep the fields relevant to the query, although this is not needed as the alert is populated using _id\n| keep\n    Esql.script_block_pattern_count,\n    Esql.script_block_length,\n    Esql.script_block_tmp,\n    powershell.file.*,\n    file.path,\n    file.name,\n    process.pid,\n    powershell.sequence,\n    powershell.total,\n    _id,\n    _version,\n    _index,\n    host.name,\n    host.id,\n    agent.id,\n    user.id\n\n// Filter for scripts that match the pattern at least once\n| where Esql.script_block_pattern_count >= 1"
      }
    ]
  },
  "automation": {
    "safe": [
      "Add recommendation as Sentinel incident comment.",
      "Run enrichment queries.",
      "Create ServiceNow SecOps task."
    ],
    "approval_required": [
      "Contain or disable the affected host/account.",
      "Any change to production configuration."
    ]
  },
  "escalation_criteria": [
    "Obfuscated Files or Information activity observed on a privileged account or critical system.",
    "Activity follows or precedes other suspicious behaviour in the same investigation.",
    "Automated triage cannot confidently rule out malicious intent."
  ],
  "false_positive_considerations": [
    "Legitimate administrative or maintenance activity matching this pattern.",
    "Approved security testing or red team exercise.",
    "Known benign software producing similar telemetry."
  ],
  "confluence": {
    "title": "T1027 - Obfuscated Files or Information Response Guidance",
    "labels": [
      "mitre",
      "attack",
      "d3fend",
      "secops",
      "basyrix"
    ],
    "sections": [
      "summary",
      "d3fend_mappings",
      "investigation_steps",
      "response_actions",
      "queries",
      "automation",
      "escalation_criteria",
      "false_positive_considerations"
    ]
  }
}