YASS (Yet another steganographic scheme) is a newly developed JPEG steganographic method. Through embedding data in the randomized 8×8 blocks which do not coincide with the 8×8 grid used in JPEG compression, it effectively disables the self-calibration process popularly used in today's JPEG steganalyzers. However, with YASS' complicated embedding procedure, the intra- and interblock dependency among the quantized DCT coefficients belonging to the original image is disturbed after the secret message embedding. Furthermore, because of the randomly selection of an 8×8 block within a large block and the necessary utilization of error correction code, the amount of information that YASS can embed is largely reduced. In this paper a study on security performance of YASS is reported. Our experimental results have demonstrated that 1) the steganalyzers which utilizes intra- and/or inter-block correlation of JPEG coefficients can break YASS, 2) with embedding the same amount of information bits, the security of YASS is not stronger than that of MB1 when some today's blind JPEG steganalyzers are used.