Multiple integer overflows in Microsoft ASN.1 library (MSASN1.DLL) as used in LSASS.EXE CRYPT32.DLL and other Microsoft executables and libraries on Windows NT 4.0 2000 and XP allow remote attackers to execute arbitrary code via ASN.1 BER encodings with (1) very large length fields that cause arbitrary heap data to be overwritten or (2) modified bit strings.