On 14/09/2015 17:40, Michael Heide wrote: > Am Mon, 14 Sep 2015 16:39:15 +0200 schrieb Jakob Bohm <jb-openssl at wisemo.com>: > >> Where can I see the actual file (Not the virustotal >> description of the signature), I would need to look >> at the actual details to make sense of this. > I think you have to use some kind of a subscription and use their APIs to access their database. > > I've searched the web and found: > http://admdownload.adobe.com/bin/live/flashplayer18ax_ha_install.exe > (md5: 0c6b5474223a4b5bf90a46844ed865db) > > Seems to be a file with the same criteria here. That one is a big surprise to me. It seems that as late as in August 17 2015 (4 weeks ago), Symantec/Verisign issued a timestamp signature, whose "EncryptedDigest"was made on the following non-standard input: 00|01|FF...|00|00 87 34 69 20 D5 4C 68 F4 B1 30 6DEA 3E 40 CC B7 71 AC 1D The first parts (00|01|FF...|00) form the PKCS#1 padding for a PCS#1 v1.x signature. But the last part is a 20 byte string that doesn't seem to match anything permitted by PKCS#1 v1.5 (or v2.1). I also note that the SignerInfo specifies "version 1" (aka PKCS#7 v1.5), so I don't think this could be the elusive PKCS#7 v1.4 signature format. It might hypothetically be an SHA1 SUM, but the initial 00 byte looks strange. I am struggling a bit with trying to figure out what bytes are covered by the hash value, so far I have failed to manually extract a relevant subset of of the message, but I may have made some basic mistake since I usually don't do this by hand. Well, the good news is that at least the PKCS#1 padding is still there, which makes it a lot less vulnerable than what your e-mails made me think. > ... >> And this file is very new (July 2015), are you sure >> it uses the nonstandard EncryptedDigest calculation? > No, I'm not. Maybe I'm doing something wrong. I don't know. It seems not, now I really wonder what is going on. Enjoy Jakob -- Jakob Bohm, CIO, Partner, WiseMo A/S. http://www.wisemo.com Transformervej 29, 2860 S?borg, Denmark. Direct +45 31 13 16 10 This public discussion message is non-binding and may contain errors. WiseMo - Remote Service Management for PCs, Phones and Embedded -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mta.openssl.org/pipermail/openssl-users/attachments/20150914/39ab954b/attachment-0001.html>
