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

Static analysis result for SHA-256 547b7811be0bfac9…

MALICIOUS

Office (OOXML) / .XLSX

200.3 KB Created: 2021-03-22 13:13:33 UTC Authoring application: Microsoft Excel 15.0300
MD5: 1b197c7db4d1a335cf20e3101c305714 SHA-1: 3575c4e1d08edcd56d8092cc1527bcfea7806dcd SHA-256: 547b7811be0bfac99f3ea814e72a491c77b2dffde17b3e9e0c7716ec0b48e661
140 Risk Score

Malware Insights

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

This XLSX file contains a Workbook_Open VBA macro, a common technique for initial execution. The macro exhibits VBA Chr string obfuscation and uses a GetObject call, indicating it's designed to execute further code. The presence of a 'macros.bas' file and the 'vbaProject.bin' further confirm macro-based execution. The script likely downloads and executes a second-stage payload, but the specific payload and its destination could not be determined from the provided static analysis.

Heuristics 4

  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
  • 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
6411d103bdd383fa88e7810d7afb6c27fad8b085d2c9e404d71788a7d62477f2
vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 9388 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 22 Chr/ChrW string-construction calls.
vbaProject_00.bin
b8aba95ae6fc8d3df820ae7639e2ad2b1f396c71707b8d4f77740f88fb60f82e
vba-project OOXML VBA project: xl/vbaProject.bin 61440 bytes