Xls.Dropper.Agent-8733268-0 — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 5ec5b4a0f0996bb3…

MALICIOUS

Office (OLE) / .XLS

84.5 KB Created: 2020-07-01 09:35:58 Authoring application: Microsoft Excel
MD5: af7e97f63ad511c14ac73d572a02149f SHA-1: a8e3fb93c273300107b2d07b3f63e928721f31a9 SHA-256: 5ec5b4a0f0996bb3715d6528f906e1a1ed40383a8b648bf22a06c4549d6767cd
260 Risk Score

Malware Insights

Xls.Dropper.Agent-8733268-0 · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The file is an Excel spreadsheet containing a Workbook_Open macro. This macro is heavily obfuscated and uses CreateObject to execute a second-stage payload. ClamAV identified the sample as Xls.Dropper.Agent-8733268-0, indicating its dropper functionality. The presence of a Workbook_Open macro strongly suggests it was delivered as a spearphishing attachment.

Heuristics 6

  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • ClamAV: Xls.Dropper.Agent-8733268-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-8733268-0
  • 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 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
8fb7c90e70665c571d231b9be5e56ac2cbd46b320cac7003f1e34778d3f5f8b2		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 2148 bytes

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