Executive brief
A vulnerability in the SunOS operating system running on Sparc 20 hardware allows any user with local access to crash the entire system. By attempting to read from a specific graphics device file, a user can trigger a kernel panic, leading to a total service outage. This can be used to disrupt operations or facilitate other attacks by taking the machine offline.
Technical details
A denial of service vulnerability exists in SunOS 4.1.4 on Sparc 20 architectures due to improper handling of read operations on the /dev/tcx0 TCX frame buffer device. A local, unprivileged attacker can trigger a kernel panic by executing simple read commands (e.g., 'cat' or 'ls') against the device node. The root cause appears to be a failure in the device driver to handle unexpected access patterns on systems where the TCX hardware may not be present or properly initialized. A suggested workaround is the removal of the /dev/tcx0 device node if the hardware is not in use.
Affected products
- Sun Microsystems SunOS 4.1.4
Timeline
- 1997-05-19: disclosed: Initial disclosure on Bugtraq mailing list.
- 1997-05-19: advisory: NVD published date.