That depends when this attack was first conducted and when this variant of the cryptanalysis on MD5 was made as Marc Stevens sums up [1]: More interestingly, t

That depends when this attack was first conducted and when this variant of the cryptanalysis on MD5 was made as Marc Stevens sums up [1]: More interestingly, the results have shown that not our published chosen-prefix collision attack was used, but an entirely new and unknown variant. Therefore it is not unreasonable to assume that the particular chosen-prefix collision attack variant underlying Flame had already been in development before June 2009. This has led to our conclusion that the design of Flame is partly based on world-class cryptanalysis. [1] http://www.cwi.nl/news/2012/cwi-cryptanalist-discovers-new-cryptographic-attack-variant-in-flame-spy-malware http://www.cwi.nl/news/2012/cwi-cryptanalist-discovers-new-c...