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

Static analysis result for SHA-256 0e179d44066e33d3…

MALICIOUS

Office (OOXML) / .DOC

94.0 KB Created: 2019-06-12 19:40:00 UTC Authoring application: Microsoft Office Word 14.0000
MD5: 6e36dc0710756dd2fe5354873418a5d8 SHA-1: 1ae7fb15df19cb38dc72092e036076c5b878d4bd SHA-256: 0e179d44066e33d35b3fdb50b37710dfa4803bad4a5006e4e8e666a997ffff30
542 Risk Score

Malware Insights

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

This document leverages the CVE-2017-11882 vulnerability in the Equation Editor to embed and execute a malicious RTF object. This object, in turn, contains a PE executable and exploits CVE-2017-8759 for OLE activation, leading to the execution of a secondary payload. The presence of altChunk RTF with auto-updating executable objects strongly indicates a malicious intent to deliver an exploit.

Heuristics 12

  • CVE-2017-11882 — Equation Editor FONT record overflow critical CVE likely CVE_2017_11882
    (in altChunk RTF word/afchunk.rtf) Equation Editor MTEF contains an overlong FONT typeface field, the vulnerable copy primitive for CVE-2017-11882. This is stronger evidence than the Equation Editor CLSID alone because it identifies the malformed record that drives code execution in EQNEDT32.EXE.
  • CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759
    (in altChunk RTF word/afchunk.rtf) 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.
  • 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.
  • Equation Editor CLSID critical RTF_EQUATION_EDITOR
    (in altChunk RTF word/afchunk.rtf) Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • PE header (with DOS stub) in hex data critical RTF_MZ_HEX
    (in altChunk RTF word/afchunk.rtf) Hex-encoded PE (MZ + DOS stub) found inside RTF — likely an embedded executable payload
  • altChunk RTF auto-updates embedded executable object critical OOXML_ALTCHUNK_RTF_AUTOUPDATE_PE
    OOXML document imports an embedded RTF through altChunk; the RTF contains OLE object data, forces object update, and carries a hex-encoded PE payload. This is a stronger compound exploit-loader shape than a generic altChunk RTF wrapper, but it is not tied to a single CVE unless the nested RTF object primitive also matches one.
  • ClamAV: Rtf.Exploit.CVE_2017_11882-6584355-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Exploit.CVE_2017_11882-6584355-1
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    (in altChunk RTF word/afchunk.rtf) RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • Package object class high RTF_OBJCLASS_PACKAGE
    (in altChunk RTF word/afchunk.rtf) OLE Package object — can wrap arbitrary files
  • OLE object data medium RTF_OBJDATA
    (in altChunk RTF word/afchunk.rtf) RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    (in altChunk RTF word/afchunk.rtf) 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.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/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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000186f0.bin
5eda582369843f39739a140ee2d9609d0a067bbd6b9488b60cc845462320fffa
rtf-objdata-decoded RTF \objdata at offset 0x186F0 135402 bytes
objdata_01_off0005abee.bin
779bb6a1471b4d72c1c6ced5c694c90ab7c774aeb456cc17604065d28839a0e6
rtf-objdata-decoded RTF \objdata at offset 0x5ABEE 3546 bytes