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

Static analysis result for SHA-256 60afae48613bb6cd…

MALICIOUS

Office (OOXML) / .XLSM

412.5 KB Created: 2020-05-28 07:15:19 UTC Authoring application: Microsoft Excel 16.0300
MD5: 33914b809b0d5621f2a3939db69dc258 SHA-1: 2189f96851663010bd5f16b1c2c9a353ca1c22fe SHA-256: 60afae48613bb6cd966eadb913940af2f05fed3e132d19d48b941c7434365ff2
384 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File T1105 Ingress Tool Transfer

The Workbook_Open macro in the VBA script decodes a Base64 string which contains a PowerShell command. This command downloads an executable file named 'siihost.exe' from 'http://111.90.149.244/siihost.exe' to the temporary directory and then executes it. The use of WScript.Shell and CreateObject further supports the malicious intent.

Heuristics 10

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • VBA Base64-decoded Shell command stager critical OLE_VBA_BASE64_SHELL_COMMAND_STAGER
    VBA auto-exec macro decodes Base64 string literals into command or script-launch text and executes the result with Shell. This catches cmd/cscript/PowerShell/VBS launchers hidden from plain keyword matching.
  • ClamAV: Xls.Downloader.DridexGreen09213-9890103-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.DridexGreen09213-9890103-0
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Suspicious extracted artifact info 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.
  • 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://111.90.149.244/siihost.exe

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
874a141fe5447793115f6227bf3545ac1010a798cd5ce07ca6ca2abfe446d28a
vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2958 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
vbaProject_00.bin
d8c64a86fab1b50d320feab553c5aeb57f642c9cf19ecae81cd961188cf5d436
vba-project OOXML VBA project: xl/vbaProject.bin 19456 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).