OLE stream size disagrees with its sector chain

OLE_STREAM_LEN_MISMATCH

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medium OLE_STREAM_LEN_MISMATCH

What it means

Direntry size field claims more bytes than the FAT-walked sector chain can carry.

Why it fires

Readers that allocate from the size field and copy from the chain read out-of-bounds bytes. A simple structural shape that has appeared in several Office parser memory-corruption bugs.

Other Office heuristics

OLE_VBA_AFFINE_MSI_DOWNLOADER OLE_VBA_AUTOEXEC_FRAGMENTED_SHELL OLE_VBA_DESTRUCTIVE_WORKBOOK_SHUTDOWN OLE_VBA_BIDIRECTIONAL_MACROCOPY_REPLICATION OOXML_BRAND_LINK_MISMATCH_LURE CVE_2016_7262 POLYGLOT_OOXML_REL_COMMAND OLE_RAW_PCODE_CROSS_DOCUMENT_REPLICATION OLE_VBA_CROSS_WORKBOOK_REPLICATION OOXML_XLM_DANGEROUS_FN OFFICE_DEFAULT_PASSWORD_VBA_DROP_EXEC OFFICE_EMBEDDED_SWF EMBEDDED_OFFICE_CHILD_STATIC_TRIAGE OFFICE_EMBEDDED_MACRO_OBJECT OLE_EMBEDDED_EXE OLE_VBA_EMBEDDED_PE_DROPPER OLE_ENCRYPTED_AND_MALFORMED CVE_2017_11882_EQUATION_NATIVE_CMD_RELATED CVE_2017_11882 OLE_EQUATION_OLE10NATIVE_DOWNLOADER OLE_MTEF_NATIVE_CODE_STUB OLE_EQUATION_OLE10NATIVE_SHELLCODE OOXML_XLM_MACRO_IN_WORKSHEET OLE_XLS5_LAROUX_MACRO_VIRUS