Junos OS: EX2300, EX3400 Series: Veriexec signature checking not enforced in specific versions of Junos OS

Summary

Veriexec is a kernel-based file integrity subsystem in Junos OS that ensures only authorized binaries are able to be executed. Due to a flaw in specific versions of Junos OS, affecting specific EX Series platforms, the Veriexec subsystem will fail to initialize, in essence disabling file integrity checking. This may allow a locally authenticated user with shell access to install untrusted executable images, and elevate privileges to gain full control of the system. During the installation of an affected version of Junos OS are installed, the following messages will be logged to the console: Initializing Verified Exec: /sbin/veriexec: Undefined symbol "__aeabi_uidiv" /sbin/veriexec: Undefined symbol "__aeabi_uidiv" /sbin/veriexec: Undefined symbol "__aeabi_uidiv" veriexec: /.mount/packages/db/os-kernel-prd-arm-32-20190221.70c2600_builder_stable_11/boot/brcm-hr3.dtb: Authentication error veriexec: /.mount/packages/db/os-kernel-prd-arm-32-20190221.70c2600_builder_stable_11/boot/contents.izo: Authentication error ... This issue affects Juniper Networks Junos OS: 18.1R3-S4 on EX2300, EX2300-C and EX3400; 18.3R1-S3 on EX2300, EX2300-C and EX3400.