/usr/5bin/su in SunOS 4.1.3 and earlier uses a search path that includes the current working directory (.), which allows local users to gain privileges via Trojan horse programs.
NFS on SunOS 4.1 through 4.1.2 ignores the high order 16 bits in a 32 bit UID, which allows a local user to gain root access if the lower 16 bits are set to 0, as fixed by the NFS jumbo patch upgrade.
Vulnerability in integer multiplication emulation code on SPARC architectures for SunOS 4.1 through 4.1.2 allows local users to gain root access or cause a denial of service (crash).
The portmapper may act as a proxy and redirect service requests from an attacker, making the request appear to come from the local host, possibly bypassing authentication that would otherwise have taken place. For example, NFS file systems could be mounted through the portmapper despite export restrictions.
SunOS 4.1.2 and earlier allows local users to gain privileges via "LD_*" environmental variables to certain dynamically linked setuid or setgid programs such as (1) login, (2) su, or (3) sendmail, that change the real and effective user ids to the same user.
rdist in various UNIX systems uses popen to execute sendmail, which allows local users to gain root privileges by modifying the IFS (Internal Field Separator) variable.