Valyria — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 5020aa7375a87748…

MALICIOUS

Office (OLE) / .XLS

829.5 KB Created: 2018-12-06 20:43:11 Authoring application: Microsoft Excel
MD5: 68261372815c10de36132bfb033ee530 SHA-1: abec43afb7b690ad35c7d2bac9262beab90527cd SHA-256: 5020aa7375a877484aa72332255213614bf13126494f1c9cd39b098211ffaca2
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 PowerShell

The sample is a malicious Excel file containing VBA macros that are triggered upon opening the Workbook_Open event. The macro code is heavily obfuscated, consisting of large arrays of numeric values, and uses the Shell() function and WScript.Shell object to execute commands on the system. ClamAV identifies the family as Valyria, and the heuristic firings for VBA p-code auto-execution and Shell calls are consistent with this behavior.

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
c3baa3c99e107b0a5f50526c7fb9382ee29a3debf9ed9aa044adfef7edbfa565		 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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