Re: [openpgp] Spoofing OpenPGP and S/MIME Signatures in Emails

[Albrecht Dreß <[e-mail]>]

Hi,

On 30.04.19 14:29, ilf wrote:
> https://github.com/RUB-NDS/Johnny-You-Are-Fired

While testing the MUA Balsa <https://pawsa.fedorapeople.org/balsa/> using the proof-of-concept messages provided on Github, I noticed that many (most? all?) of the RFC 3156 message parts are not recognised by it.  Looking at the message source (e.g. “Attack Class 'MIME', Test 'M1' (PGP/MIME)”), it appears that the header

   Content-Type: multipart/signed; boundary="BOUNDARY"; protocol="application/pgp-signature"

is missing the “micalg” parameter.  However, RFC 3156, sect. 5 states that

> OpenPGP signed messages are denoted by the "multipart/signed" content type, described in [RFC1847]

which defines in sect. 2.1

> Required parameters: boundary, protocol, and micalg

Consequently, Balsa (and maybe other MUA's, too) simply ignores such multipart/signed parts as they don't comply with the standard.

Did you omit the parameter intentionally, i.e. did I miss something interpreting the standards (typically, the value is never used), or are these proof-of-concept messages broken?

Thanks in advance,
Albrecht.