Xls.Dropper.Agent-7848942-0 — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 b2f433c17b3d5edb…

MALICIOUS

Office (OOXML) / .XLSM

80.4 KB Created: 2020-05-20 00:55:31 UTC Authoring application: Microsoft Excel 12.0000
MD5: 5320134ae7b656dbd8e6877ff49d9e44 SHA-1: b732922169b1d087070a009375ae966a9b33a38e SHA-256: b2f433c17b3d5edb3406717d10be2de3b713def2a3484d9342822c7191c0f673
340 Risk Score

Malware Insights

Xls.Dropper.Agent-7848942-0 · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1059.003 Windows Command Shell

This XLSM file contains a Workbook_Open macro that utilizes character-shifting functions (Asc, Chr, Mid) to decode and execute a command via Shell(). The ClamAV detection name 'Xls.Dropper.Agent-7848942-0' strongly suggests this is a dropper designed to download and execute a secondary payload. The presence of a Workbook_Open macro and the use of Shell() are key indicators of this malicious behavior.

Heuristics 7

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • VBA character-shift decoded Shell command critical OLE_VBA_ASC_CHR_SHIFT_SHELL
    VBA auto-exec macro stores an encoded command string, decodes it with a Mid/Asc/Chr character-shift loop, and passes the recovered text to Shell. This is a high-confidence command stager.
  • ClamAV: Xls.Dropper.Agent-7848942-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-7848942-0
  • 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
  • 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

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
2fb842d5fd06e3a77dd586edddc2b7c42c52ffa0e264969baf430984d0b88a46		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2319 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
7e2a214e40afb4e566fced111b28aa3483cadc0c2534b3ff38e7b7460df052ab		 vba-project OOXML VBA project: xl/vbaProject.bin 17408 bytes
Detection
ClamAV: Xls.Dropper.Agent-7848942-0
Obfuscation or payload: unlikely

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