Xls.Dropper.Agent-7370611-0 — Office (OLE) malware analysis

Static analysis result for SHA-256 931cbb463ef1754c…

MALICIOUS

Office (OLE)

204.5 KB First seen: 2015-09-19
MD5: 21b28135253eae4b8377b5ce670ad790 SHA-1: cbc0dab2a4b360fdb567cc39a386adf1d6d71767 SHA-256: 931cbb463ef1754c14ae5606edf4232044d2ce949ddd717cf7e31a759387cda8
148 Risk Score

Malware Insights

Xls.Dropper.Agent-7370611-0 · confidence 95%

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic T1105 Ingress Tool Transfer

The file is detected as malicious by ClamAV with the signature Xls.Dropper.Agent-7370611-0. Heuristics indicate an OLE document with an appended executable payload and a large slack space, suggesting it's designed to hide malicious content. Although the VBA macros themselves contain no executable statements, the overall structure and appended payload strongly suggest a dropper functionality, likely delivered via spearphishing.

Heuristics 4

  • ClamAV: Xls.Dropper.Agent-7370611-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-7370611-0
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 209,456 bytes but its declared streams total only 117,220 bytes — 92,236 bytes (44%) 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).
  • OLE file has appended executable-looking payload bytes high OLE_APPENDED_PAYLOAD
    OLE compound file contains a large high-entropy region beyond the declared major streams and that region includes shellcode, PE, or loader API markers. This is a payload-carrier signal, not a specific CVE attribution by itself.
  • VBA project contains no executable statements low OLE_VBA_MACROS
    Document contains a VBA project, but extracted modules only contain attributes/options/comments and no executable statements.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 671 bytes
SHA-256: 11993efa3cba2fc6c51e24c164f8f6ee10667f9dc6a11024b0790cb1a63a4c71
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 = "ListView2, 1, 1, MSComctlLib, ListView"

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

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