Strange SSH flaw raised by French porter

Along similar lines, I remember a flaw in SSH reported by the French porter of the software who produced a version with a weaker cryptographic key to comply with French law at the time. I'm not competent to judge the reality of the problem, but he certainly thought it was a backdoor.

From:

ftp://ftp.nluug.nl/pub/metalab/docs/linux-doc-project/lin...

I often like to point out an incomprehensible weakness of the protocol concerning the "padding" (known as covered channel): in both version 1 and 2 the packets, have a length which is a multiple of 64 bits, and are padded with a random number. This is quite unusual and therefore sparing a classical fault that is well known in encrypting products: a "hidden" (or "subliminal") channel. Usually , we "pad" with a verified sequence as for example, give the value n for the byte rank n (self describing padding). In SSH, the sequence being (by definition) randomized, it cannot be checked. Consequently, it is possible that one of the parties communicating could pervert / compromise the communication for example used by a third party who is listening. One can also imagine a corrupted implementation unknown by the two parties (easy to realize on a product provided with only binaries as generally are commercial products). This can easily be done and in this case one only needs to "infect" the client or the server. To leave such an incredible fault in the protocol, even though it is universally known that the installation of a covered channel in an encryption product is THE classic and basic way to corrupt the communication, seems unbelievable to me . It can be interesting to read Bruce Schneier's remarks concerning the implementation of such elements in products influenced by government agencies. (http://www.counterpane.com/crypto-gram-9902.html#backdoors).

I will end this topic with the last bug I found during the portage of SSH to SSF (French version of SSH), it is in the coding of Unix versions before 1.2.25. The consequence was that the random generator produced ... predictable... results (this situation is regrettable in a cryptographic product, I won't go into the technical details but one could compromise a communication while simply eavesdropping). At the time SSH's development team had corrected the problem (only one line to modify), but curiously enough without sending any alert, not even a mention in the "changelog" of the product... one wouldn't have wanted it to be known, he wouldn't have acted differently. Of course there is no relationship with the link to the above article.