Malicious Office (OLE) / .XLS — malware analysis report

Static analysis result for SHA-256 33ac30c98fee70f7…

MALICIOUS

Office (OLE) / .XLS

43.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 05f213b51aea121d3b43e17856cb68a4 SHA-1: 528d5a795e79a26cacca9eac7a9ae62b3d5fc28c SHA-256: 33ac30c98fee70f75935e6968568e97759c87a65d665503a4522fc04c9220bd2
200 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: User Execution: Malicious File T1059.001 Command and Scripting Interpreter: PowerShell T1059.003 Command and Scripting Interpreter: Windows Command Shell T1105 Ingress Tool Transfer

The sample is an Excel 4.0 macro-enabled spreadsheet that attempts to lure the user into enabling macros. The embedded XLM macro sheet contains an Auto_Open entry that uses dangerous functions like RUN and EXEC. The macro is designed to download a payload from 'http://asengjewelry.com/mmyubbktjopl/' using rundll32.exe and DllRegisterServer, and also attempts to establish persistence via a Run key.

Heuristics 5

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
b68def77bf3d78b7c0be9f30ad60574365101f4a762f9255957bf746dbc07ff7		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1729 bytes

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