An attacker with physical access to a PAX Point Of Sale device with ProlinOS through 2.4.161.8859R can boot it in management mode, enable the XCB service, and then list, read, create, and overwrite files with MAINAPP permissions.

An unsigned-library issue was discovered in ProlinOS through 2.4.161.8859R. This OS requires installed applications and all system binaries to be signed either by the manufacturer or by the Point Of Sale application developer and distributor. The signature is a 2048-byte RSA signature verified in the kernel prior to ELF execution. Shared libraries, however, do not need to be signed, and they are not verified. An attacker may execute a custom binary by compiling it as a shared object and loading it via LD_PRELOAD.

An issue was discovered in ProlinOS through 2.4.161.8859R. An attacker with local code execution privileges as a normal user (MAINAPP) can escalate to root privileges by exploiting the setuid installation of the xtables-multi binary and leveraging the ip6tables --modprobe switch.

PAX Technology PAX A920 Pro PayDroid 8.1suffers from a Race Condition vulnerability, which allows attackers to bypass the payment software and force the OS to boot directly to Android during the boot process. NOTE: the vendor disputes this because the attack is not feasible: the home launcher will be loaded before any user applications.