Win.Dropper.Agent-34370 — Office (OLE) / .DOC malware analysis

Static analysis result for SHA-256 65397d7a8bda6b34…

MALICIOUS

Office (OLE) / .DOC

192.6 KB Created: 2006-04-29 01:29:00 Authoring application: Microsoft Office Word
MD5: 00cda884818be39c88110177e081d6b1 SHA-1: 7f461c651129806d159a94a316b7539b41ed367b SHA-256: 65397d7a8bda6b3486f9c29f674d9d110dfae9bb2ee6fc942931e817ecfa707d
480 Risk Score

Malware Insights

Win.Dropper.Agent-34370 · confidence 95%

MITRE ATT&CK
T1059.001 PowerShell T1203 Exploitation for Client Execution T1055 Process Injection T1105 Ingress Tool Transfer

The file exhibits characteristics of a dropper, with heuristics indicating the use of WinExec, VirtualAlloc, VirtualProtect, WriteProcessMemory, CreateRemoteThread, and LoadLibrary APIs. These functions are commonly used by malware to inject code into legitimate processes and execute secondary payloads. The presence of a NOP sled and XOR-encoded strings further supports this assessment. ClamAV identified the sample as Win.Dropper.Agent-34370.

Heuristics 11

  • Reference to WriteProcessMemory API critical SC_STR_WRITEPROCESSMEMORY
    Reference to WriteProcessMemory API
  • Reference to CreateRemoteThread API critical SC_STR_CREATEREMOTETHREAD
    Reference to CreateRemoteThread API
  • XOR-encoded strings (key 0x3B) critical SC_XOR_ENCODED
    Found 8 Windows library/API name(s) XOR-encoded with single-byte key 0x3B: 'kernel32.dll', 'kernel32.dll', 'advapi32.dll', 'wininet.dll', 'shell32.dll', 'crypt32.dll', 'shlwapi.dll', 'LoadLibraryA'
  • ClamAV: Win.Dropper.Agent-34370 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Dropper.Agent-34370
  • NOP sled detected high SC_NOP_SLED
    Found 20+ consecutive 0x90 bytes
  • Reference to WinExec API high SC_STR_WINEXEC
    Reference to WinExec API
  • Reference to LoadLibrary API high SC_STR_LOADLIBRARY
    Reference to LoadLibrary API
  • Reference to GetProcAddress API high SC_STR_GETPROCADDRESS
    Reference to GetProcAddress API
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 197,218 bytes but its declared streams total only 26,783 bytes — 170,435 bytes (86%) 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).
  • Reference to VirtualAlloc API medium SC_STR_VIRTUALALLOC
    Reference to VirtualAlloc API
  • Reference to VirtualProtect API medium SC_STR_VIRTUALPROTECT
    Reference to VirtualProtect API

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