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MITRE ATT&CK sub-technique

T1027.006 — HTML Smuggling

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T1027.006 (HTML Smuggling) is a MITRE ATT&CK sub-technique tracked in WhisperGraph, serving the Stealth tactic.

Description

Adversaries may smuggle data and files past content filters by hiding malicious payloads inside of seemingly benign HTML files. HTML documents can store large binary objects known as JavaScript Blobs (immutable data that represents raw bytes) that can later be constructed into file-like objects. Data may also be stored in Data URLs, which enable embedding media type or MIME files inline of HTML documents. HTML5 also introduced a download attribute that may be used to initiate file downloads.(Citation: HTML Smuggling Menlo Security 2020)(Citation: Outlflank HTML Smuggling 2018) Adversaries may deliver payloads to victims that bypass security controls through HTML Smuggling by abusing JavaScript Blobs and/or HTML5 download attributes. Security controls such as web content filters may not identify smuggled malicious files inside of HTML/JS files, as the content may be based on typically benign MIME types such as <code>text/plain</code> and/or <code>text/html</code>. Malicious files or data can be obfuscated and hidden inside of HTML files through Data URLs and/or JavaScript Blobs and can be deobfuscated when they reach the victim (i.e. [Deobfuscate/Decode Files or Information](https://attack.mitre.org/techniques/T1140)), potentially bypassing content filters. For example, JavaScript Blobs can be abused to dynamically generate malicious files in the victim machine and may be dropped to disk by abusing JavaScript functions such as <code>msSaveBlob</code>.(Citation: HTML Smuggling Menlo Security 2020)(Citation: MSTIC NOBELIUM May 2021)(Citation: Outlflank HTML Smuggling 2018)(Citation: nccgroup Smuggling HTA 2017)

Tactics

Related techniques

Parent technique: T1027 · Obfuscated Files or Information

Threat actors observed using this technique

© The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation.

Related pages

Pivot from T1027.006 into its tactic, related techniques and the actors that use it.

Queries

Resolves the segment to this technique or tactic.


MATCH (t:ATTACK_PATTERN {name: $id})
RETURN t.id AS id, t.name AS name, t.kind AS kind, t.description AS description
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The tactic(s) this technique serves.


MATCH (t:ATTACK_PATTERN {name: $id})-[:USES_TACTIC]->(tac:ATTACK_PATTERN)
RETURN tac.id AS id, tac.name AS name
LIMIT 10
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This id's parent technique, if it is a sub-technique.


MATCH (p:ATTACK_PATTERN {name: $parentId})
RETURN p.id AS id, p.name AS name
LIMIT 1
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Sub-techniques of this technique, if any.


MATCH (c:ATTACK_PATTERN) WHERE c.id STARTS WITH $subPrefix
RETURN c.id AS id, c.name AS name
ORDER BY c.id
LIMIT 25
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Threat actors observed using this technique.


MATCH (a:ACTOR)-[:USES_TECHNIQUE]->(t:ATTACK_PATTERN {name: $id})
RETURN a.name AS name
LIMIT 100
Run yourself →

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