### Reinterpreting and Improving the Cryptanalysis of the Flash Player PRNG

George Teseleanu

##### Abstract

Constant blinding is an efficient countermeasure against just-in-time (JIT) spraying attacks. Unfortunately, this mitigation mechanism is not always implemented correctly. One such example is the constant blinding mechanism found in the Adobe Flash Player. Instead of choosing a strong mainstream pseudo-random number generator (PRNG), the Flash Player designers chose to implement a proprietary one. This led to the discovery of a vulnerability that can be exploited to recover the initial seed used by the PRNG and thus, to bypass the constant blinding mechanism. Using this vulnerability as a starting point, we show that no matter the parameters used by the previously mentioned PRNG it still remains a weak construction. A consequence of this study is an improvement of the seed recovering mechanism from previously known complexity of $\mathcal O(2^{21})$ to one of $\mathcal O(2^{11})$.

Available format(s)
Category
Secret-key cryptography
Publication info
Published elsewhere. Minor revision.C2SI-2019
Keywords
jit spaying attacksflash player prngconstant blinding
Contact author(s)
george teseleanu @ yahoo com
History
2022-03-15: revised
See all versions
Short URL
https://ia.cr/2019/086

CC BY

BibTeX

@misc{cryptoeprint:2019/086,
author = {George Teseleanu},
title = {Reinterpreting and Improving the Cryptanalysis of the Flash Player PRNG},
howpublished = {Cryptology ePrint Archive, Paper 2019/086},
year = {2019},
note = {\url{https://eprint.iacr.org/2019/086}},
url = {https://eprint.iacr.org/2019/086}
}

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