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

Static analysis result for SHA-256 2688c742345ce61e…

MALICIOUS

Office (OOXML) / .XLSM

44.7 KB Created: 2021-10-08 10:35:53 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-08-02
MD5: 1ccf404df635e0f6e75ce299fde9a5d2 SHA-1: bb056d4208e4581a60c48a491dbb83e1807be754 SHA-256: 2688c742345ce61e419b9c8b68dfe452d40bc764284fe400f40cd0275a6e48d4
402 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File T1071.001 Web Protocols

The Workbook_Open macro contains obfuscated VBA code that, when deobfuscated, constructs and executes a PowerShell command. This command downloads a file from http://185.230.162.77/assocationfile/appmodel.exe and saves it as an executable in the temporary directory, then executes it. This indicates a downloader or dropper functionality.

Heuristics 9

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • Obfuscated VBA Shell command with URL critical OLE_VBA_OBFUSCATED_SHELL_URL
    VBA macro invokes Shell with command text assembled through decoder or string-manipulation functions and includes a URL. This is a high-confidence downloader/dropper pattern, stronger than Shell or URL evidence on their own.
  • ClamAV: Xls.Dropper.EPPlus-9802867-2 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.EPPlus-9802867-2
  • 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.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • 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://185.230.162.77/assocationfile/appmodel.exe

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
43aba37afb279d7ded0923ad7035e09d1b31fb4d8b786f38bef8f6a711aa7abb		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1277 bytes
vbaProject_00.bin
3d37ae620958cc20c2f8b589071d9d3f9545bd2c606d909f951f1e8fc68ea6e1		 vba-project OOXML VBA project: xl/vbaProject.bin 5120 bytes
Detection
ClamAV: Xls.Dropper.EPPlus-9802867-2
Obfuscation or payload: unlikely

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