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.