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

Static analysis result for SHA-256 5b3b4f424a14b3b9…

MALICIOUS

Office (OOXML) / .DOC

706.3 KB Created: 2021-07-27 08:09:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-09-25
MD5: a641586334e9538b8b385800d2029db4 SHA-1: accc9d133610b38904b2c09bb0d994fb30358ff4 SHA-256: 5b3b4f424a14b3b9a2325f2728b7f8161097c944991eba778404a4319d1ac649
430 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1105 Ingress Tool Transfer T1059.003 Windows Command Shell

The sample contains VBA macros with an AutoOpen subroutine that utilizes Shell() and CreateObject() to download and execute a second-stage payload. The heuristic 'OLE_VBA_HTTP_DROP_EXEC' specifically indicates VBA downloading a file via HTTP and saving it to disk, which is then likely executed. The presence of cmd.exe references further supports the execution of downloaded content. The ClamAV detection 'Doc.Dropper.Agent-6412232-1' also aligns with this dropper behavior.

Heuristics 11

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • VBA downloads and writes a file to disk critical OLE_VBA_HTTP_DROP_EXEC
    VBA reads an HTTP response body and writes it to disk (ADODB.Stream SaveToFile). Combined with the auto-exec/Shell paths this is a download-drop dropper even when the COM ProgIDs are built dynamically to evade keyword scanning.
  • ClamAV: Doc.Dropper.Agent-6412232-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6412232-1
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • cmd.exe reference in VBA high OLE_VBA_CMD
    cmd.exe reference in VBA
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • External hyperlinks (2) low OOXML_EXTERNAL_HYPERLINKS
    Document contains 2 external hyperlinks — clickable URLs are stored as external relationships. First target: https://www.microsoft.com/en-us/videoplayer/embed/RE1FGlM
  • 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://arsenal.30cm.tw/picaball.exe
    • 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/2016/wordml/cid
    • 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
    • http://ns.adobe.com/xap/1.0/
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/sType/ResourceRef#
    • http://ns.adobe.com/xap/1.0/sType/ResourceEvent#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/photoshop/1.0/
    • https://www.microsoft.com/en-us/videoplayer/embed/RE1FGlM

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
982ec755929fc29fa0710599403527b768423e425c9bc2b964a39f22d9faa367
vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 4075 bytes
vbaProject_00.bin
f19c57d1f57e44c7bd7204d63e9dd4690738b86d1075f235156b20014f71d05b
vba-project OOXML VBA project: word/vbaProject.bin 15360 bytes
Detection
ClamAV: Doc.Dropper.Agent-6412232-1
Obfuscation or payload: unlikely