Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 00844905bcda6e29…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:44:11 Authoring application: Microsoft Excel First seen: 2021-10-07
MD5: 0b8f923d2d41ed5eda412fd681f04122 SHA-1: 63b311c29694963b231ff68fdcfc0ecafd1d1139 SHA-256: 00844905bcda6e291ccbb4bfb48d158c530cd0659c9b298096d7ffa4dc16db28
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open defined name, which is a known technique for executing malicious code upon opening the workbook. The macro sheet contains formulas that call dangerous APIs, including 'RUN', suggesting it is designed to execute arbitrary commands. This functionality is commonly used 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) 6557 bytes
SHA-256: 443d5902f04a8d524314ec58fb0479a32335b64f4c3284065d315913e337f564
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     15 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  goeGCk
' 0018     20 LABEL : Cell Value, String Constant - AFuIW len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A134 
' 0018     24 LABEL : Cell Value, String Constant - bEqvMgIbq len=0 
' 0018     23 LABEL : Cell Value, String Constant - bvyJuLSq len=0 
' 0018     21 LABEL : Cell Value, String Constant - cgdNuu len=0 
' 0018     26 LABEL : Cell Value, String Constant - CTCnaemMutA len=0 
' 0018     21 LABEL : Cell Value, String Constant - dluuuD len=0 
' 0018     26 LABEL : Cell Value, String Constant - fwkCmpDkLyL len=0 
' 0018     27 LABEL : Cell Value, String Constant - IHaTgVlanikn len=0 
' 0018     27 LABEL : Cell Value, String Constant - jmZDNeQVKoYW len=0 
' 0018     22 LABEL : Cell Value, String Constant - mdyyJyA len=0 
' 0018     25 LABEL : Cell Value, String Constant - NOdptQbIpR len=0 
' 0018     25 LABEL : Cell Value, String Constant - qPuRMyQDbn len=0 
' 0018     22 LABEL : Cell Value, String Constant - QySDiWv len=0 
' 0018     21 LABEL : Cell Value, String Constant - qzWefv len=0 
' 0018     25 LABEL : Cell Value, String Constant - SWFpKbynct len=0 
' 0018     27 LABEL : Cell Value, String Constant - UJQjgRMLoZBH len=0 
' 0018     26 LABEL : Cell Value, String Constant - VboJcBvGcos len=0 
' 0018     27 LABEL : Cell Value, String Constant - VMiteGGlnDha len=0 
' 0018     24 LABEL : Cell Value, String Constant - YeUyimfoE len=0 
' 0018     21 LABEL : Cell Value, String Constant - ZzCkDP 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

... (truncated)

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