Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4a8add08f4aa5d64…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:26:28 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: e1746d9bb2b6435086b8e3a4cce6c719 SHA-1: e679ba68a833d9fbfbcfe843096bdd9aa71b5a90 SHA-256: 4a8add08f4aa5d642795247c1528042dd19f44b3cb2f787e483669d2fb9f1076
140 Risk Score

Malware Insights

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

The file contains critical heuristic firings indicating the presence of Excel 4.0 macros with an Auto_Open function, which is a known technique for executing malicious code. The macro sheet contains a reference to 'Auto_Open', suggesting it will run automatically upon opening the workbook. The presence of dangerous formula APIs like RUN further confirms its malicious intent, likely to download and execute a secondary 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) 6432 bytes
SHA-256: 362027c86a2259f4c0927537fc1bcb8384c20c65314b96b986cc92f89f098b2e
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  IEt
' 0018     27 LABEL : Cell Value, String Constant - aGYiuYOSXFwz len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I145 
' 0018     22 LABEL : Cell Value, String Constant - EkpJMBS len=0 
' 0018     21 LABEL : Cell Value, String Constant - eqdifR len=0 
' 0018     22 LABEL : Cell Value, String Constant - EVFOJhB len=0 
' 0018     20 LABEL : Cell Value, String Constant - FMgvZ len=0 
' 0018     22 LABEL : Cell Value, String Constant - GnwWcQH len=0 
' 0018     20 LABEL : Cell Value, String Constant - gZWav len=0 
' 0018     21 LABEL : Cell Value, String Constant - HBCFRq len=0 
' 0018     21 LABEL : Cell Value, String Constant - hqJvFD len=0 
' 0018     26 LABEL : Cell Value, String Constant - hwjisiJYwDf len=0 
' 0018     26 LABEL : Cell Value, String Constant - iogUgPWhvmU len=0 
' 0018     20 LABEL : Cell Value, String Constant - JifYk len=0 
' 0018     22 LABEL : Cell Value, String Constant - NxizKxu len=0 
' 0018     24 LABEL : Cell Value, String Constant - okASsQSPj len=0 
' 0018     22 LABEL : Cell Value, String Constant - QgSVQwa len=0 
' 0018     25 LABEL : Cell Value, String Constant - rOrNgppCiI len=0 
' 0018     26 LABEL : Cell Value, String Constant - VYHZzRsJHOl len=0 
' 0018     23 LABEL : Cell Value, String Constant - XCHUfCQW len=0 
' 0018     23 LABEL : Cell Value, String Constant - yXcQVzBC len=0 
' 0018     21 LABEL : Cell Value, String Constant - zMwzfd 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     10 LABELSST : Cell
... (truncated)

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