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

Static analysis result for SHA-256 7b89cc890e8b3eb2…

MALICIOUS

Office (OLE) / .XLS

111.5 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel
MD5: 12cf4446a265fdd2b50d045084ca3529 SHA-1: 1f233d857384cc642230303734249c7997be70af SHA-256: 7b89cc890e8b3eb2f2cfd37869072deab89e0d65c140d2bf627c29df7f46ad61
280 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1105 Ingress Tool Transfer

The XLS file exhibits a significant slack space anomaly and critically, contains an embedded PE executable. Heuristics indicate the potential use of WinExec, CreateProcess, VirtualAlloc, LoadLibrary, and GetProcAddress APIs, suggesting the embedded executable is likely dropped and executed. The embedded executable itself is the primary IOC. The lack of document body text or script content limits further analysis of the initial lure.

Heuristics 7

  • Embedded PE executable critical OLE_EMBEDDED_EXE
    MZ/PE header found inside document — possible embedded executable
  • Reference to WinExec API high SC_STR_WINEXEC
    Reference to WinExec API
  • Reference to CreateProcess API high SC_STR_CREATEPROCESS
    Reference to CreateProcess 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 114,176 bytes but its declared streams total only 24,565 bytes — 89,611 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).
  • Reference to VirtualAlloc API medium SC_STR_VIRTUALALLOC
    Reference to VirtualAlloc API

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_office_0000c060.exe
b14e20d219ad99dee572e5c70f638146136e770bb054ef4f06cef3a4df4d2fdd		 embedded-pe Office MZ+PE at offset 0xC060 64928 bytes

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