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

Static analysis result for SHA-256 90455eac71a034f7…

MALICIOUS

Office (OOXML) / .XLSM

70.9 KB Created: 2020-01-28 19:47:00 UTC Authoring application: Microsoft Excel 16.0300
MD5: 3c323368bd38c3356ba3f9bfc3cd9bda SHA-1: c77ab727d67cfbd3c8bdff55f241fc1d42b2838c SHA-256: 90455eac71a034f7d2823317a9847c1cb09906b95abd748ac7bae33e3fb99c3d
110 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution T1059.003 Command and Scripting Interpreter: Windows Command Shell T1105 Ingress Tool Transfer T1059.005 Command and Scripting Interpreter: Visual Basic

The sample is an XLSM file containing VBA macros. It uses a "yellow bar" and a fake tour lure to prompt the user to enable content. Upon enabling, the `Workbook_Activate` subroutine triggers `Prefix0`, which constructs and executes a batch file named `Uusajwtsndq.bat`. This batch file, in turn, downloads a file named `Modzimo.pif` from `http://stubhost.online/fold/Modzimo.pif` using PowerShell and executes it. The VBA script also reconstructs a PowerShell command to download the payload.

Heuristics 5

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • VBA project inside OOXML medium OOXML_VBA
    Document contains vbaProject.bin — VBA macros present
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • External hyperlinks (3) low OOXML_EXTERNAL_HYPERLINKS
    Document contains 3 external hyperlinks — clickable URLs are stored as external relationships. First target: http://go.microsoft.com/fwlink/?LinkId=846286
  • 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://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/sType/ResourceEvent#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/photoshop/1.0/
    • http://ns.adobe.com/tiff/1.0/
    • http://ns.adobe.com/exif/1.0/
    • http://go.microsoft.com/fwlink/?LinkId=846286
    • http://go.microsoft.com/fwlink/?LinkId=844969

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
feeda91c062bd1084fa5fe9423663f98af8b8091c89b6cf5a995d41f58632e18		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2673 bytes
vbaProject_00.bin
54ada42783bc02ace0cccba9cceef89b577d9bda5dfed57a0d31fc282a715e42		 vba-project OOXML VBA project: xl/vbaProject.bin 20992 bytes

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