Malicious Office (OLE) / .XLS — malware analysis report

Static analysis result for SHA-256 ff10c55319dee95e…

MALICIOUS

Office (OLE) / .XLS

115.0 KB
MD5: c302fad772d90c827d46bdbd89966963 SHA-1: 7c800cb7b1b1fa28a51e919c78361c513d80d077 SHA-256: ff10c55319dee95e281669998f657544b82a80e9de9d862a0bf46697b9752452
220 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1140 Deobfuscate/Decode Files or Information T1027 Obfuscated Files or Information

The sample is an Excel file exhibiting characteristics of malicious intent, including the presence of XOR-encoded strings and calls to Windows API functions such as WinExec, LoadLibrary, and GetProcAddress. The OLE slack anomaly suggests hidden or packed data. While no specific URLs were identified as malicious, the combination of encoding and API calls strongly indicates the file's purpose is to download and execute a second-stage payload.

Heuristics 6

  • XOR-encoded strings (key 0x03) critical SC_XOR_ENCODED
    Found 8 Windows library/API name(s) XOR-encoded with single-byte key 0x03: 'VirtualAlloc', 'VirtualAlloc', 'VirtualAllocEx', 'VirtualProtect', 'VirtualProtectEx', 'CreateProcessA', 'WriteProcessMemory', 'ReadProcessMemory'
  • 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 117,760 bytes but its declared streams total only 56,346 bytes — 61,414 bytes (52%) 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).
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.microsoft.com
    • https://www.verisign.com/rpa
    • http://ocsp.verisign.com/ocsp/status0
    • https://www.verisign.com/rpa0
    • http://crl.microsoft.com/pki/crl/products/CodeSignPCA.crl0

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