Executive brief
A security flaw in older versions of Solaris, SunOS, and BSD-based operating systems causes the system to ignore security permissions on local communication channels known as UNIX domain sockets. This allows any user logged into the system to connect to these channels, even if they are supposed to be restricted. An attacker could use this to send malicious data to running programs, potentially disrupting services or gaining unauthorized control over their operations.
Technical details
A vulnerability exists in the handling of UNIX domain sockets (AF_UNIX) where the operating system kernel fails to enforce filesystem-level access permissions. While a socket may appear to have restrictive permissions (e.g., 0700), the kernel allows any local user to successfully call connect() to that socket. This is a local attack vector requiring no special privileges. An attacker can exploit this to interact with local services, inject bogus data, or disrupt the operations of applications that rely on socket permissions for security. The issue was addressed in BSD 4.4 and later versions, but persisted in various commercial Unix implementations of that era.
Affected products
- Sun Microsystems Solaris 2.x
- Sun Microsystems SunOS 4.x
- BSD BSD-based operating systems before 4.4
Timeline
- 1997-05-17: disclosed: Initial report on Bugtraq regarding Solaris x86 2.5
- 1997-05-17: advisory