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

Static analysis result for SHA-256 5b1e622fdb9ccb34…

MALICIOUS

Office (OOXML) / .DOC

139.8 KB Created: 2021-02-07 17:10:00 UTC Authoring application: Microsoft Office Word 16.0000
MD5: b1145e02bd7a23198ce4c6aea4eac018 SHA-1: 27cdc609746de043a7b4e0a727b8e0dcafaed765 SHA-256: 5b1e622fdb9ccb34e1df0f32f73f829855b9996f8132463a86c3db124654b55b
322 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1105 Ingress Tool Transfer T1204.002 Malicious File

The sample contains VBA macros, specifically an AutoOpen macro, which is a common technique for executing malicious code upon opening a document. The script attempts to download a file from 'http://gstator.com/header.jpg' and save it as 'C:\users\Public\rzw.jpg'. This indicates a downloader functionality, aiming to fetch and execute a second-stage payload.

Heuristics 8

  • 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.Downloader.BlueWord-9845926-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.BlueWord-9845926-0
  • 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
  • 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
  • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
cb6597afef5471ed4b2e857d8e3fa103189a7b6d51ddc96921c0ab2506491164		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2226 bytes
vbaProject_00.bin
b9a1ebc60de52dae0e3ae6837af7c8c69a1facd8b9c49d067632bb0bf143acf1		 vba-project OOXML VBA project: word/vbaProject.bin 99328 bytes
Detection
ClamAV: Doc.Downloader.BlueWord-9845926-0
Obfuscation or payload: unlikely

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