Valyria — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 d4c39820192ae288…

MALICIOUS

Office (OLE) / .XLS

686.5 KB Created: 2018-12-06 20:43:11 Authoring application: Microsoft Excel
MD5: 2efe46a6dc5165c9fda8839403115a3c SHA-1: 0e449888239ae05ce4c4eae8f01fbcfed2c3afd7 SHA-256: d4c39820192ae288fde7d999da4656ed93c402f1b7479f0a6e5aa9f903a41876
400 Risk Score

Malware Insights

Valyria · confidence 70%

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1204.002 User Execution: Malicious File T1059.001 Command and Scripting Interpreter: PowerShell

The sample is an Excel file containing a large, heavily obfuscated VBA macro that uses Workbook_Open to auto-execute. The script uses CreateObject("WScript.Shell") and Shell() calls to execute system commands, which is typical of a downloader pattern. The ClamAV detection 'Xls.Malware.Valyria' directly supports the attribution to the Valyria family.

Heuristics 9

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • ClamAV: Xls.Malware.Valyria-10032137-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Malware.Valyria-10032137-0
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • 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.
  • 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 macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
0e132f503319ca32fb1a589dbc86100d9c8f6d5723fc37cc1f76b21d55732203		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 693770 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 shell/COM execution token(s). Carved artifact contains 516 long base64-like blob(s). Carved macro source contains an auto-exec entry point and execution/download terms.

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