Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 67858f2c0ee3cf0f…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:46:50 Authoring application: Microsoft Excel First seen: 2021-11-02
MD5: a740e66caed2ed3fa8ef25a516b0bb83 SHA-1: 02f9277af421476e93268f12ee71d7f2415a5e8b SHA-256: 67858f2c0ee3cf0f7023eca03f0b2810c4e29e21a8d8dd8fe3492bb40051ab71
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 heuristics also flag the use of dangerous formula APIs within the macro, such as RUN=0, suggesting the execution of external commands. The macro's purpose is likely to download and execute a second-stage payload, although the specific commands are truncated in the provided evidence.

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) 6526 bytes
SHA-256: 16f1c6cdfc1f962b6b1878786ecebf22744abccbdc41ff617683b8cf8db6b584
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     13 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  bQNb
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A185 
' 0018     23 LABEL : Cell Value, String Constant - AWgKmGeW len=0 
' 0018     20 LABEL : Cell Value, String Constant - aXyAU len=0 
' 0018     21 LABEL : Cell Value, String Constant - dRiNnt len=0 
' 0018     20 LABEL : Cell Value, String Constant - Dwuwm len=0 
' 0018     25 LABEL : Cell Value, String Constant - fzhzHKuBgi len=0 
' 0018     22 LABEL : Cell Value, String Constant - gKHuDnJ len=0 
' 0018     27 LABEL : Cell Value, String Constant - gvdKwHsrbqkW len=0 
' 0018     22 LABEL : Cell Value, String Constant - KGAmLOf len=0 
' 0018     27 LABEL : Cell Value, String Constant - MeZcHJsEjwJs len=0 
' 0018     26 LABEL : Cell Value, String Constant - nONkJtKyuon len=0 
' 0018     26 LABEL : Cell Value, String Constant - oLCeYYHpoZW len=0 
' 0018     20 LABEL : Cell Value, String Constant - PVDyx len=0 
' 0018     26 LABEL : Cell Value, String Constant - rGOnvOADQHG len=0 
' 0018     27 LABEL : Cell Value, String Constant - RKCzMIGYVsgQ len=0 
' 0018     27 LABEL : Cell Value, String Constant - RTNXfzyxMIsl len=0 
' 0018     23 LABEL : Cell Value, String Constant - tOHVaNCD len=0 
' 0018     22 LABEL : Cell Value, String Constant - wwIyWJu len=0 
' 0018     20 LABEL : Cell Value, String Constant - xVLJs len=0 
' 0018     26 LABEL : Cell Value, String Constant - yjpHBvGGRis len=0 
' 0018     21 LABEL : Cell Value, String Constant - yuxOab 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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