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).
Critical vulnerability in the integer multiplication emulation code on older SunOS systems allows for local privilege escalation to root, granting attackers complete control. This flaw, dating back to the early 1990s, presents a significant risk to any legacy systems still in operation, potentially leading to system compromise or a denial-of-service condition.
Step 1: Trigger the Vulnerability: A local user executes a program designed to trigger the integer multiplication vulnerability. This program crafts specific multiplication operations that will cause an integer overflow within the kernel's emulation code.
Step 2: Overflow Execution: The crafted multiplication operation is performed by the kernel's emulation code. Due to the lack of proper bounds checking, the result of the multiplication overflows, leading to an incorrect value.
Step 3: Data Corruption: The incorrect result from the overflow is used to overwrite critical kernel data structures. This could include process credentials (UID, GID), or other sensitive data.
Step 4: Privilege Escalation (or DoS): If the attacker successfully overwrites the process's UID with 0 (root), they gain root privileges. Alternatively, if the overwritten data leads to a kernel crash, a denial-of-service condition occurs.
The vulnerability stems from a flaw in the integer multiplication emulation code within the SunOS kernel, specifically on SPARC architectures. The code likely fails to properly handle integer overflow conditions during multiplication operations. When a specially crafted multiplication operation is performed, the result can wrap around, leading to an incorrect value. This incorrect value can then be used to overwrite critical kernel data structures, such as the process credentials (UID, GID), or to trigger a crash. The root cause is a lack of proper input validation and error handling in the multiplication emulation routines, allowing for a integer overflow to occur. This can lead to a privilege escalation scenario where a local user can gain root access by manipulating the process's effective user ID.