Malicious Office (OOXML) / .DOCX — malware analysis report

Static analysis result for SHA-256 a728696cba3c76b8…

MALICIOUS

Office (OOXML) / .DOCX

219.5 KB Created: 2020-01-30 08:31:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2026-06-01T07:00:00+00:00
MD5: 5a70104215956eda639a83557dcfd7f4 SHA-1: b3dd392d6741b4656cd5173dd99a9234c78eaafe SHA-256: a728696cba3c76b8224bf5eb523ed6dcd5f9812d3d0ea030320cf97357be90d1
302 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is a DOCX file that leverages the CVE-2017-11882 vulnerability in the Equation Editor. This is achieved through an embedded RTF object, which is then activated via OLE object manipulation. The exploitation of Equation Editor indicates a likely attempt to download and execute a secondary payload.

Heuristics 8

  • CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759
    (in altChunk RTF word/echn.xml) RTF contains a hex-encoded OLE1 object for Msxml2.SAXXMLReader.6.0 followed by an embedded OLE compound document, and the document requests OLE activation. This matches the RTF staging shape used for CVE-2017-8759 SOAP/WSDL parser code injection.
  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    (in altChunk RTF word/echn.xml) RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • altChunk imports embedded RTF (RTF injection) critical OOXML_ALTCHUNK_RTF
    Document inlines an embedded RTF via an aFChunk relationship and a <w:altChunk> body element. This is the canonical RTF-injection wrapper used to smuggle RTF exploits (Equation Editor / URL Moniker / objdata) past DOCX-only scanners. Word opens the wrapper and executes the RTF inline. Recursing into the RTF for the exact exploit primitive.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    (in altChunk RTF word/echn.xml) RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    (in altChunk RTF word/echn.xml) RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • OLE object data medium RTF_OBJDATA
    (in altChunk RTF word/echn.xml) RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    (in altChunk RTF word/echn.xml) RTF contains \objemb — embedded OLE object
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.microsoft.com/office/word/2010/wordprocessingCanvas
    • http://schemas.microsoft.com/office/drawing/2014/chartex
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/officeDocument/2006/math
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawing
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing
    • http://schemas.openxmlformats.org/wordprocessingml/2006/main
    • http://schemas.microsoft.com/office/word/2010/wordml
    • http://schemas.microsoft.com/office/word/2012/wordml
    • http://schemas.microsoft.com/office/word/2015/wordml/symex
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroup
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInk
    • http://schemas.microsoft.com/office/word/2006/wordml
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShape

Extracted artifacts 10

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000a967c.bin
58831f8908bddf28132ebd92d6a1ed85dd6a3f9c23b082be23952c4e8802d79e		 rtf-objdata-decoded RTF \objdata at offset 0xA967C 194749 bytes
objdata_01_off00113773.bin
b0eab8e216039bf751b0d996d507cabb9f1d51e449f6d0252e69a55aa00d845d		 rtf-objdata-decoded RTF \objdata at offset 0x113773 693522 bytes
rtf_svb_0038c725.zip
b461da4154fae7bb965448788af03a71a043eb99efb0e1486728dba51d84fefb		 rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x38C725 967 bytes
rtf_svb_0038d6c9.zip
fd1e102bcb6b99544d5f496230f01cdc210d50001dfd8788c72c164a41bbc17a		 rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x38D6C9 964 bytes
rtf_svb_0038e7ac.zip
dccebec6ff30f32dea492b008c7a93c18ee44b84efc33f5170556a0e447c561b		 rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x38E7AC 962 bytes
rtf_svb_0038f9f1.zip
65de83f9da1995ceca4030d239f160f1147ba8bc65cff69e56d96e1036f8a1f4		 rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x38F9F1 964 bytes
rtf_svb_00390a5e.zip
39f288b305c47c2fd0fd8bd70152a78751d03b94e58ef4697d97c379caca4dee		 rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x390A5E 964 bytes
rtf_svb_00391514.zip
23b49ebcf55d2f54277e67ed137a0426cb9515e6c8114b1839bfd2e0b780ce39		 rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x391514 962 bytes
rtf_svb_00392f4c.zip
c9a120b53568a6dad7025751988d0b74512060f8a13d1eb00a0bd65499d61adf		 rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x392F4C 966 bytes
rtf_svb_003949eb.zip
82c8d8674a89c4d2c1e4fd0de8103680307b4b4228464f322ce03570939e979c		 rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x3949EB 965 bytes

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