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

Static analysis result for SHA-256 a61b2eafcf397150…

MALICIOUS

Office (OOXML) / .DOC

117.8 KB Created: 2023-06-26 12:57:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2023-07-03
MD5: d227874863036b8e73a3894a19bd25a0 SHA-1: 2400b169ee2c38ac146c67408debc9b4fa4fca5f SHA-256: a61b2eafcf39715031357df6b01e85e0d1ea2e8ee1dfec241b114e18f7a1163f
282 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1059 Command and Scripting Interpreter

The sample utilizes an altChunk to import an RTF document, which in turn contains an OLE object. This OLE object is automatically linked and configured to update, exploiting CVE-2017-0199 to fetch and execute a payload from the URL http://74.50.94.156/MSHTML_C7/start.xml. This technique is commonly used by macro-based malware to download and execute second-stage malicious content.

Heuristics 7

  • CVE-2017-0199 (OLE2Link / remote URL Moniker) critical CVE likely CVE_2017_0199
    (in altChunk RTF word/afchunk.rtf) RTF contains a URL Moniker OLE link whose decoded target is remote. Office can fetch and process the response through the CVE-2017-0199 OLE2Link attack path, but the server-side content type is not proven statically.
  • 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.
  • ClamAV: Rtf.Exploit.CVE_2017_0199-6335035-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Exploit.CVE_2017_0199-6335035-0
  • Automatically linked OLE object high RTF_OBJAUTLINK
    (in altChunk RTF word/afchunk.rtf) RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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.
  • OLE object data medium RTF_OBJDATA
    (in altChunk RTF word/afchunk.rtf) RTF contains 2 \objdata section(s) — embedded OLE objects
  • 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://74.50.94.156/MSHTML_C7/start.xml
    • http://schemas.openxmlformats.org/drawingml/2006/main
    • http://schemas.openxmlformats.org/drawingml/2006/picture
    • http://schemas.microsoft.com/office/word/2010/wordprocessingCanvas
    • http://schemas.microsoft.com/office/drawing/2014/chartex
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartex
    • http://schemas.microsoft.com/office/drawing/2015/10/21/chartex
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartex
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartex
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartex
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartex
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartex
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartex
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.microsoft.com/office/drawing/2016/ink
    • http://schemas.microsoft.com/office/drawing/2017/model3d
    • 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/2018/wordml/cex
    • http://schemas.microsoft.com/office/word/2016/wordml/cid
    • http://schemas.microsoft.com/office/word/2018/wordml
    • http://schemas.microsoft.com/office/word/2020/wordml/sdtdatahash
    • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000026de.bin
df658c0fce44d9d20e8156cae3f4f0614f3f1afc94701f9234c9ba653dd665ed
rtf-objdata-decoded RTF \objdata at offset 0x26DE 2901 bytes
objdata_01_off00003e68.bin
1705b454e944bcbf49040a6caed488232d7488f40d1fee0f44abda7aad54cca1
rtf-objdata-decoded RTF \objdata at offset 0x3E68 3625 bytes