Tickets :: [#13851] 8bit/binary Content-Transfer-Encoding should not be used via SMTP channel

6.0.0-alpha12

6/7/25

Summary	8bit/binary Content-Transfer-Encoding should not be used via SMTP channel
Queue	IMP
Queue Version	6.1.7
Type	Bug
State	Not A Bug
Priority	1. Low
Owners
Requester	orvos.peter (at) microsec (dot) hu
Created	02/09/2015 (3771 days ago)
Due
Updated	02/10/2015 (3770 days ago)
Assigned
Resolved	02/10/2015 (3770 days ago)
Github Issue Link
Github Pull Request
Milestone
Patch	No

02/10/2015 07:58:43 AM	orvos (dot) peter (at) microsec (dot) hu	Comment #4	Reply to this comment
This was fixed long ago. You are using an old version of IMP. Thank you for the information; unfortunately I could not pinpoint out the problem and its solution in the change logs. In this case I inform the administrators of the ISP that they should upgrade. (BTW: I cannot imagine how they could start a new webmail interface with already such an old version...) Once again, thank you.

02/10/2015 06:16:22 AM	Michael Slusarz	Comment #3 State ⇒ Not A Bug Priority ⇒ 1. Low	Reply to this comment
This was fixed long ago. You are using an old version of IMP.

02/09/2015 10:05:19 AM	orvos (dot) peter (at) microsec (dot) hu	Comment #2	Reply to this comment
The headers and the faulty line of such an email: [Show Quoted Text - 59 lines][Hide Quoted Text] To: =?utf-8?b?Q8OpZ2LDrXLDs3PDoWcg?= =?utf-8?b?S2Fwb3N2w6Fy?= <somogy@iroda.e-cegjegyzek.hu> Subject: Csutak Invest Kft. User-Agent: Internet Messaging Program (IMP) H5 (6.1.7) Content-Type: multipart/mixed; boundary="=_Zk6NQ_Z--vmpf3m4hTCAgA5" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit This message is in MIME format. --=_Zk6NQ_Z--vmpf3m4hTCAgA5 Content-Type: multipart/alternative; boundary="=_TqhbzP27zaajdtV4lT2U9g4" This message is in MIME format. --=_TqhbzP27zaajdtV4lT2U9g4 Content-Type: text/plain; charset=UTF-8; format=flowed; DelSp=Yes Content-Description: =?utf-8?b?U3rDtnZlZ2VzIA==?= =?utf-8?b?bGV2w6ls?= Content-Disposition: inline --=_TqhbzP27zaajdtV4lT2U9g4 Content-Type: text/html; charset=UTF-8 Content-Description: HTML =?utf-8?b?bGV2w6ls?= Content-Disposition: inline <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd"> <html> <head> <!--a75c305b1c0a6022--><meta http-equiv="content-type" content="text/html; charset=utf-8"> <title></title> </head> <body style="font-family:Arial;font-size:14px"> </body> </html> --=_TqhbzP27zaajdtV4lT2U9g4-- --=_Zk6NQ_Z--vmpf3m4hTCAgA5 Content-Type: application/vnd.eszigno3+xml; name=CsutakInvestKft20150206.es3 Content-Disposition: attachment; size=932622; filename=CsutakInvestKft20150206.es3 Content-Transfer-Encoding: 8bit <?xml version="1.0" encoding="UTF-8"?> ... <ds:Object Id="O2S417b2960-b68c-4ec2-a201-94a748735ad9"><QualifyingProperties Target="#S417b2960-b68c-4ec2-a201-94a748735ad9" Id="QPS417b2960-b68c-4ec2-a201-94a748735ad9"><SignedProperties Id="XS417b2960-b68c-4ec2-a201-94a748735ad9"><SignedSignatureProperties><SigningTime>2015-02-06T07:48:33Z</SigningTime><SigningCertificate><Cert><CertDigest><ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/><ds:DigestValue>fA6x2zgBVGtvuIhfTOCGhax1Tet1PbfZd3eIc8vpBSM=</ds:DigestValue></CertDigest><IssuerSerial><ds:X509IssuerName>emailAddress=info@e-szigno.hu,CN=Qualified e-Szigno CA 2009,O=Microsec Ltd.,L=Budapest,C=HU</ds:X509IssuerName><ds:X509SerialNumber>9461980820244724050855867008010</ds:X509SerialNumber></IssuerSerial></Cert></SigningCertificate><SignaturePolicyIdentifier><SignaturePolicyImplied/></SignaturePolicyIdentifier><SignerRole><ClaimedRoles><ClaimedRole>ügyvéd</ClaimedRole></ClaimedRoles></SignerRole></SignedSignatureProperties></SignedProperties><UnsignedProper ties><UnsignedSignatureProperties><SignatureTimeStamp Id="T2ed324d4-11b4-4bd9-a475-f175cde97d79"><ds:CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315"/><EncapsulatedTimeStamp Id="ET2ed324d4-11b4-4bd9-a475-f175cde97d79">MIIItgYJKoZIhvcNAQcCoIIIpzCCCKMCAQMxDzANBglghkgBZQMEAgEFADCCAREG The line-break had broken the name of an XML tag...

02/09/2015 10:01:16 AM	orvos (dot) peter (at) microsec (dot) hu	Comment #1 Priority ⇒ 3. High Patch ⇒ No Milestone ⇒ Queue ⇒ IMP Summary ⇒ 8bit/binary Content-Transfer-Encoding should not be used via SMTP channel Type ⇒ Bug State ⇒ Unconfirmed	Reply to this comment
Sorry, if the problem has already been solved (6.1.7 is not the most recent of IMP), but I couldn't find such bug reports searching your tickets. Our problem is, that an ISP started to use IMP as its webmail, and since that point we started to receive malformed attachment contents. The problem is that the XML based content is attached with Content-Transfer-Encoding: 8bit, while it contained lines longer than 1000 characters. Referring to Rfc 2045 (MIME): [Show Quoted Text - 16 lines][Hide Quoted Text] 6. Content-Transfer-Encoding Header Field Many media types which could be usefully transported via email are represented, in their "natural" format, as 8bit character or binary data. Such data cannot be transmitted over some transfer protocols. For example, RFC 821 (SMTP) restricts mail messages to 7bit US-ASCII data with lines no longer than 1000 characters including any trailing CRLF line separator. It is necessary, therefore, to define a standard mechanism for encoding such data into a 7bit short line format. Proper labelling of unencoded material in less restrictive formats for direct use over less restrictive transports is also desireable. This document specifies that such encodings will be indicated by a new "Content- Transfer-Encoding" header field. This field has not been defined by any previous standard. Accordingly 8bit and binary Content-Transfer-Encodings can be used for ex. HTTP POSTs, however these are not to be used if the transmission channel is SMTP, since Rfc 821 (SMTP) allows any SMTP servers to break lines longer than 1000 characters or convert bodies to 7bit by will. Since IMP is webmail client we might state that every MIME structures it creates will be transferred via SMTP, therefore the usage of 8bit and binary transfer-encodings are contraindicated. Thx for your kind help!