Ursnif — Office (OOXML) / .DOC malware analysis

Static analysis result for SHA-256 133eaec108dcdf48…

MALICIOUS

Office (OOXML) / .DOC

50.5 KB Created: 2021-06-28 10:46:00 UTC Authoring application: Microsoft Office Word 16.0000
MD5: ffad9afed8f30d780cac0808da1c5d3f SHA-1: b838575fe38390f411e85505607023b6764101a1 SHA-256: 133eaec108dcdf485a65616e0b26d8ffe1781e795b49bef6021c51679bf92c7a
264 Risk Score

Malware Insights

Ursnif · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059.003 Windows Command Shell T1105 Ingress Tool Transfer

The sample is a malicious OOXML document containing a VBA macro. The Document_Open macro triggers the main subroutine, which in turn calls a function that uses Shell() to execute 'cmd /c ' followed by a path to save a file. The script also contains logic to XOR-decode a string, likely a payload, which is then written to the file 'c:\users\public\doubleBorderInt.h'. This indicates the document's purpose is to download and execute a second-stage payload.

Heuristics 8

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • ClamAV: Doc.Downloader.Ursnif06210-9875010-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Ursnif06210-9875010-0
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • 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
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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.microsoft.com/office/drawing/2015/9/8/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
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/photoshop/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/sType/ResourceEvent#
    • http://ns.adobe.com/xap/1.0/sType/ResourceRef#
    • http://ns.adobe.com/tiff/1.0/
    • http://ns.adobe.com/exif/1.0/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
51aa4651fdd6979ef04aabe10e016ae9877f7b9d5fcc88d148daf1611346de9c		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1403 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).
vbaProject_00.bin
9db97e7c5590068048307f00f6a5fb362abd08eccd7c8c6ad1d3f05ffe776e49		 vba-project OOXML VBA project: word/vbaProject.bin 17408 bytes

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