Sload — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 19039c37b95cf5af…

MALICIOUS

Office (OOXML) / .XLSM

26.6 KB Created: 2022-09-11 21:50:09 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-09-25
MD5: d65a7b3dc3dd0c1e06de0ded093dce3c SHA-1: 37b3afc16d0c3ff64b6b12fb996dc509e543d8a9 SHA-256: 19039c37b95cf5af1dbb2646a6ce6aea34d28f5b129db1880099e3b2dd22e5e9
420 Risk Score

Malware Insights

Sload · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1071.001 Web Protocols T1105 Ingress Tool Transfer T1204.002 Malicious File T1566.001 Spearphishing Attachment T1566.002 Spearphishing Link

The sample is an XLSM file containing a Workbook_Open macro that is obfuscated but designed to download and execute a second-stage payload. The heuristic OLE_VBA_HTTP_DROP_EXEC specifically indicates that the VBA code downloads a file via HTTP and saves it to disk, which is a common technique for malware delivery. The ClamAV detection name 'Xls.Malware.Sload-7135989-0' further supports the classification as Sload malware.

Heuristics 9

  • VBA downloads and writes a file to disk critical OLE_VBA_HTTP_DROP_EXEC
    VBA reads an HTTP response body and writes it to disk (ADODB.Stream SaveToFile). Combined with the auto-exec/Shell paths this is a download-drop dropper even when the COM ProgIDs are built dynamically to evade keyword scanning.
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • ClamAV: Xls.Malware.Sload-7135989-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Malware.Sload-7135989-0
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
50b0481ecd182a42ba5e08f0e9e258c38518ce6284b1e32b64e9c1ba334f86eb		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 7992 bytes
vbaProject_00.bin
6eb5afedf43d6851b7909cf3a85f5d5379a9026b44ca61e25a6a1d24a4876346		 vba-project OOXML VBA project: xl/vbaProject.bin 47616 bytes
Detection
ClamAV: Xls.Malware.Sload-7135989-0
Obfuscation or payload: unlikely

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