ASA-2019-00497 – Wind River VxWorks: Heap overflow in DHCP Offer/ACK parsing in ipdhcpc

A specially crafted DHCP packet may cause overflow of heap-allocated memory on VxWorks system using DHCP. The attacker must share LAN with the device as DHCP packets is not forwarded by IP-routers. This vulnerability only affects systems that use the included DHCP client. DHCP packets may go past the local area network (LAN) via DHCP relays, but is otherwise confined to the LAN. The DHCP client may be used in VxWorks and in the bootrom. Bootrom using DHCP/BOOTP is only vulnerable during the boot process, not after the VxWorks image has booted. This defect may be used to overwrite the heap, which most likely results in a crash later on a task requesting memory from the heap. In the worst-case scenario, this vulnerability can potentially lead to RCE.