Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 d12b7d10ac74a8fd…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:46:56 Authoring application: Microsoft Excel First seen: 2021-07-10
MD5: 9e7e0c7b86da306d503eb23b02b6e863 SHA-1: aecd8b86bee61edffe81801bc5206fcdc5a9db1a SHA-256: d12b7d10ac74a8fd98f3fc09870462d986b8782641757fccd32143b76bc1bc1e
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding indicating automatic execution upon opening. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary code. While the exact payload is not discernible from the provided macro listing, the technique strongly implies an attempt to download and execute a second-stage payload.

Heuristics 3

  • 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.
  • 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.

FilenameKindSourceSize
xlm_macros.txt xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6788 bytes
SHA-256: 50eadc1ebf7f3defbecd9e7e070b8e072e3e832bb195ae7a1d78cc3397252450
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  mWEYNthdl
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G162 
' 0018     27 LABEL : Cell Value, String Constant - bGZfCsoyHlIg len=0 
' 0018     24 LABEL : Cell Value, String Constant - fNILpzOwh len=0 
' 0018     21 LABEL : Cell Value, String Constant - hTroDD len=0 
' 0018     20 LABEL : Cell Value, String Constant - hUqCl len=0 
' 0018     23 LABEL : Cell Value, String Constant - KZlAPIAu len=0 
' 0018     23 LABEL : Cell Value, String Constant - nKPrwFgU len=0 
' 0018     26 LABEL : Cell Value, String Constant - roqmmYZGjdn len=0 
' 0018     20 LABEL : Cell Value, String Constant - rsbQL len=0 
' 0018     27 LABEL : Cell Value, String Constant - tqjeTdmlabHn len=0 
' 0018     21 LABEL : Cell Value, String Constant - TxmmVn len=0 
' 0018     21 LABEL : Cell Value, String Constant - UBxNfd len=0 
' 0018     21 LABEL : Cell Value, String Constant - UMqAfc len=0 
' 0018     26 LABEL : Cell Value, String Constant - USniHcqsahs len=0 
' 0018     20 LABEL : Cell Value, String Constant - vjDkJ len=0 
' 0018     27 LABEL : Cell Value, String Constant - VZEJhHONutAj len=0 
' 0018     26 LABEL : Cell Value, String Constant - yatpbXuRTpr len=0 
' 0018     27 LABEL : Cell Value, String Constant - YhDQMKVZfGpb len=0 
' 0018     22 LABEL : Cell Value, String Constant - yJgYiZo len=0 
' 0018     27 LABEL : Cell Value, String Constant - yMkDvrMsjxip len=0 
' 0018     21 LABEL : Cell Value, String Constant - ZeCfei len=0 
' 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
' 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
' 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
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd 
... (truncated)

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