Office (OLE) malware analysis — malicious · 48789b12a7c8f2d8

MALICIOUS

Office (OLE)

187.0 KB Created: 1996-12-17 01:32:42 Authoring application: Microsoft Excel First seen: 2019-06-27

MD5: bb7330f85072478bee44d9e2ce4e5e44 SHA-1: 0d9e888f2bdb5a40d9c4c5b58affc87f4bf76c72 SHA-256: 48789b12a7c8f2d89dad6b79e2a46c4a1b3309b8f2df59111c07beacef038762

400 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution

The file is an Excel document that triggers a critical heuristic for CVE-2009-3129, indicating exploitation of a record overflow vulnerability. High-severity heuristics for CreateProcess, ShellExecute, WriteProcessMemory, CreateRemoteThread, and LoadLibrary suggest the exploit is used to load and execute malicious code. No document body or scripts were extracted, but the combination of the CVE exploit and process manipulation APIs strongly indicates a malicious payload execution.

Heuristics 9

CVE-2009-3129 — Excel FEATHEADER record overflow critical CVE exact CVE_2009_3129

Workbook BIFF stream contains a FEATHEADER (Feature Header) record with anomalous size (record_size=23, isf=2, cbHdrData=4294967295). Legitimate FEATHEADER records are tiny (<100 bytes) and carry cbHdrData values that fit in the record body; the value here is the documented CVE-2009-3129 exploit primitive — cbHdrData drives a memcpy with attacker-controlled size, leading to memory corruption and code execution in Excel 2007/2003.
Reference to WriteProcessMemory API critical SC_STR_WRITEPROCESSMEMORY

Reference to WriteProcessMemory API
Reference to CreateRemoteThread API critical SC_STR_CREATEREMOTETHREAD

Reference to CreateRemoteThread API
Reference to CreateProcess API high SC_STR_CREATEPROCESS

Reference to CreateProcess API
Reference to ShellExecute API high SC_STR_SHELLEXEC

Reference to ShellExecute 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 191,511 bytes but its declared streams total only 24,565 bytes — 166,946 bytes (87%) 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

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