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

Static analysis result for SHA-256 7857a221d9ccc1d4…

MALICIOUS

Office (OOXML) / .DOCX

219.5 KB Created: 2020-01-30 08:31:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2026-06-01T06:00:00+00:00
MD5: 4bf338918525f83ead5c6ac204badd1d SHA-1: 3e1969d3f959425704191914ef837a6f89d254b7 SHA-256: 7857a221d9ccc1d43c92a4aa44eba3f31eeccc291d95fcc17b395c6912f0c748
302 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is a malicious OOXML document that leverages the altChunk feature to import RTF content. Critical heuristics indicate exploitation of CVE-2017-11882 and CVE-2017-8759 via the Equation Editor and MSXML components, respectively. These vulnerabilities allow for arbitrary code execution when the document is opened, likely leading to the download and execution of a secondary payload.

Heuristics 8

  • CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759
    (in altChunk RTF word/dler.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/dler.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/dler.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/dler.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/dler.xml) RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    (in altChunk RTF word/dler.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
fb386f39f1ea2c007b12d4bf6972db4aa26408a8cf8b71a0557284e32533742e		 rtf-objdata-decoded RTF \objdata at offset 0xA967C 194749 bytes
objdata_01_off00113773.bin
61536e989884eaf7de7640abb2660276c7d75bdb90607a096bf87bd8b4997b90		 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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