The SECURITY_CONTAINER structure specifies a SECURITY_DESCRIPTOR structure ([MS-DTYP] section 2.4.6), which contains security information.

 typedef struct SECURITY_CONTAINER {
   DWORD cbBuf;
   [size_is(cbBuf), unique] BYTE* pSecurity;
 } SECURITY_CONTAINER;

cbBuf: The size, in bytes, of the buffer that is pointed to by the pSecurity member.

pSecurity: An optional pointer to a self-relative SECURITY_DESCRIPTOR structure.