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

Static analysis result for SHA-256 a85cd14fbd869e05…

MALICIOUS

Office (OOXML) / .XLSM

431.1 KB Created: 2021-08-19 14:03:52 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2022-04-12
MD5: aac1337cb3c5ade70b68e4c06dc66d3d SHA-1: 0c79389de81b54d0e7b5a45f23ef822d57bda030 SHA-256: a85cd14fbd869e0531fccf34750d9e98d6148d44882d4c957223b374301d75db
382 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample is an XLSM file containing a Workbook_Open macro that executes a command using cmd.exe. This command utilizes certutil.exe to download a second-stage executable from the URL http://100.26.109.199/r-7/loader/uploads/0367451020030851img.exe and then executes it. This indicates a downloader or dropper functionality.

Heuristics 9

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • LOLBin reference in VBA critical OLE_VBA_LOLBIN
    LOLBin reference in VBA
  • 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
  • cmd.exe reference in VBA high OLE_VBA_CMD
    cmd.exe reference in VBA
  • Suspicious extracted artifact high 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.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains vbaProject.bin — 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://100.26.109.199/r-7/loader/uploads/0367451020030851img.exe

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
1552ac6832d151d523eb96146cf4c816b730e3e4c92c3cbfbbc1d296b737a48c		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1111 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved macro source contains an auto-exec entry point and execution/download terms.
vbaProject_00.bin
a81f410b9d76e5589a6707d628a387e64457e20b601b6accf92e093b47fca114		 vba-project OOXML VBA project: xl/vbaProject.bin 5632 bytes
Detection
ClamAV: Xls.Dropper.EPPlus-9802867-2
Obfuscation or payload: unlikely

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