Malicious Office (OOXML) / .XLSM — malware analysis report

Static analysis result for SHA-256 128960fe998b69f0…

MALICIOUS

Office (OOXML) / .XLSM

276.0 KB Created: 2014-05-29 09:40:10 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-09-23
MD5: 3f2654889368cfbe875c228913f944f3 SHA-1: 6bfb221d1c2dbb41d56a235e62c797e128610f55 SHA-256: 128960fe998b69f099f47140b87adb1c9e672dcf03893efa7f527169ba4bc94e
228 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1566.002 Spearphishing Attachment

The file is an XLSM document containing a highly obfuscated VBA macro loader, indicated by critical heuristic firings like OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER. The Workbook_Open macro is present and uses CreateObject to execute code, a common technique for downloading and running secondary payloads. The VBA code includes functions for saving files to the clipboard and loading files, suggesting a multi-stage attack. The presence of external relationships and hidden sheets further supports a malicious intent.

Heuristics 7

  • 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.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject 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
  • External relationship medium OOXML_EXTERNAL_REL
    External target in xl/externalLinks/_rels/externalLink1.xml.rels: /Dokumente TeamAdmin/BerechnungsTools/Datenbank/DB.xlsx
  • Hidden worksheet (veryHidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 3 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction

Extracted artifacts 7

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
49e86b12394b2cbe6cc7843f0261751a592412952939c21655a4950dca33d683		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 14905 bytes
vbaProject_00.bin
6832ba81d61868251ed4f94a802a7ee92bc544bc85033b6e06dd8a2317e0836c		 vba-project OOXML VBA project: xl/vbaProject.bin 107008 bytes
emf_00.emf
46cffc540e18bdc1397c972360d41d90f90421150a3f38d926d398918c5048cf		 ooxml-emf OOXML EMF part: xl/media/image3.emf 2660 bytes
emf_01.emf
cfd144f5ae7ff7585f1c8efd51a0aae098638d7ffc01df304af3cbf60d64daa0		 ooxml-emf OOXML EMF part: xl/media/image4.emf 2640 bytes
emf_02.emf
d9280d43114699bdd3affac965ed74d9f99c954921c80e9ee94a142444f20aff		 ooxml-emf OOXML EMF part: xl/media/image1.emf 2652 bytes
emf_03.emf
b28ca70371f3edb0b6aed9b1e97bcc38fd69a1843955d99fbe7b8e57c500c62e		 ooxml-emf OOXML EMF part: xl/media/image5.emf 2640 bytes
emf_04.emf
08062dce34c877d189d954e8e90e0e070a0d5228b48eccddcbf80fbbdf9aab4e		 ooxml-emf OOXML EMF part: xl/media/image2.emf 1136 bytes

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