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Efail or OpenPGP is safer than S/MIME
Some may have noticed that the EFF has warnings [NB: https://www.eff.org/deeplinks/2018/05/attention-pgp-users-new-vulnerabilities-require-you-take-action-now] about the use of PGP out which I consider pretty overblown. The GnuPG team was not contacted by the researchers but I got access to version of the paper [NB: https://efail.de/] related to KMail. It seems to be the complete paper with just the names of the other MUAs redacted. Here is a response I wrote on the weekend to a reporter who inquired on this problem: The topic of that paper is that HTML is used as a back channel to create an oracle for modified encrypted mails. It is long known that HTML mails and in particular external links like <img href="tla.org/TAG"/> are evil if the MUA actually honors them (which many meanwhile seem to do again; see all these newsletters). Due to broken MIME parsers a bunch of MUAs seem to concatenate decrypted HTML mime parts which makes it easy to plant such HTML snippets. There are two ways to mitigate this attack: - Don't use HTML mails. Or if you really need to read them use a proper MIME parser and disallow any access to external links, - Use authenticated encryption. The latter is actually easy for OpenPGP because we started to use authenticated encryption (AE) since 2000 or 2001. Our AE is called MDC (Modification detection code) and was back then introduced for a very similar attack [NB: Massive Fail der gesamten in- und ausländischen Presse & inkl. EFF].
gnupg-users mailinglist, 14.05.2018
krypto_openpgp  software_krypto_gnupg  ngo_eff  itsicherheit_exploit_flaw  uni_de_fh_münster  software_mua_tb_enigmail  software_mua_html_mail  krypto_smime  itsicherheit_implementierung  itsicherheit_verdeckterkanal_data_exfil  itsicherheit_strategie  internet_protokoll_mime  krypto_openpgp_mdc  uni_nl_ku_leuven  uni_de_bochum 
9 weeks ago by kraven

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