Method of Forensic Analysis for Compromising Carrier-lock Algorithm on 3G Modem Firmware

In this paper, a new method of usage forensics memory analysis for compromising the carrier-lock algorithm was proposed. The firmware of one popular 3G modem for security issues is investigated. A binary file is reverse engineered using IDA Pro Disassembler and the carrier-lock code algorithm is found. The reproduction of arithmetic and bitwise ARM commands under the IMEI to obtain the unlock code by way of just reverse engineering become impossible because of the algorithm complexity. Therefore the existed ARM code was used to generate the unlock codes on the fly via memory forensics technique and JTAG debugger. A new method was successfully tested on a set of different modem versions.