Does gmail not accept password-protected rar files as attachments?

[Virus Guy]

I recently tried to send someone @ gmail a rar file as an attachment.
The file was about 10k. It's a small (about 50 kb) xml file. I used
winrar (offhand not sure what version I've got - there's no intuitive
way to see the version). I used the password option and also encrypted
the file name.

Gmail said this:

============
Your message was rejected by gmail-smtp-in.l.google.com for the
following reason:

5.7.0 This message was blocked because its content presents a potential
5.7.0 security issue. Please visit
5.7.0 https://support.google.com/mail/?p=BlockedMessage to review our
5.7.0 message content and attachment content guidelines.
=============

So either

(a) gmail doesn't like password-protected rar files, or

(b) gmail does real-time file-cracking and looked inside the archive and
discovered an xml file and it has a policy of rejecting xml files as
attachments.

Comments?

[Shadow]

Post by Virus Guy
The file was about 10k. It's a small (about 50 kb) xml file. I used
winrar (offhand not sure what version I've got - there's no intuitive
way to see the version). I used the password option and also encrypted
the file name.
============
Your message was rejected by gmail-smtp-in.l.google.com for the
5.7.0 This message was blocked because its content presents a potential
5.7.0 security issue. Please visit
5.7.0 https://support.google.com/mail/?p=BlockedMessage to review our
5.7.0 message content and attachment content guidelines.
=============
So either
(a) gmail doesn't like password-protected rar files

It won't allow ANY password protected files (where it can't
see the name/size of each file) and it couldn't care less about your
security. It will allow unencrypted malware through, stuff with
multiple hits on Virustotal..
[]'s

[Virus Guy]

Post by Shadow

Post by Virus Guy
So either
(a) gmail doesn't like password-protected rar files

It won't allow ANY password protected files (where it can't
see the name/size of each file) and it couldn't care less about your
security. It will allow unencrypted malware through, stuff with
multiple hits on Virustotal..

I used a hex editor on the rar file and changed the first 2 bytes.
Renamed the file from .rar to something else. Resent the file as
attachment - and this time it went through. The recipient restored the
first 2 bytes and unpacked the file normally.

[RayLopez99]

Post by Virus Guy

Post by Shadow

Post by Virus Guy
So either
(a) gmail doesn't like password-protected rar files

It won't allow ANY password protected files (where it can't
see the name/size of each file) and it couldn't care less about your
security. It will allow unencrypted malware through, stuff with
multiple hits on Virustotal..

I used a hex editor on the rar file and changed the first 2 bytes.
Renamed the file from .rar to something else. Resent the file as
attachment - and this time it went through. The recipient restored the
first 2 bytes and unpacked the file normally.

You can rename the extension of a password protected file sent to Gmail and it works to receive the file.

For a password protected file: MyFile.rar change to to MyFile.rar.ZYX will work.

RL

[Shadow]

On Wed, 10 Oct 2018 01:45:22 -0700 (PDT), RayLopez99

Post by RayLopez99

Post by Virus Guy

Post by Shadow

Post by Virus Guy
So either
(a) gmail doesn't like password-protected rar files

It won't allow ANY password protected files (where it can't
see the name/size of each file) and it couldn't care less about your
security. It will allow unencrypted malware through, stuff with
multiple hits on Virustotal..

I used a hex editor on the rar file and changed the first 2 bytes.
Renamed the file from .rar to something else. Resent the file as
attachment - and this time it went through. The recipient restored the
first 2 bytes and unpacked the file normally.

You can rename the extension of a password protected file sent to Gmail and it works to receive the file.
For a password protected file: MyFile.rar change to to MyFile.rar.ZYX will work.

Good to know.
TY
Z-Zip will open files with unknown extensions by content, so
will offer to open MyFile.rar.ZYX or MyFile.rar.aaa on a right click.
But not MyFile.rar.txt or MyFile.rar.wav.
Winrar uses extensions, so no option to open the file.
Google's AI must be braindead.
[]'s

[Apd]

Post by Shadow
Z-Zip will open files with unknown extensions by content

So will 7-Zip. Never heard of Z-Zip.

[Shadow]

Post by Apd

Post by Shadow
Z-Zip will open files with unknown extensions by content

So will 7-Zip. Never heard of Z-Zip.

Wrote it myself in secret.
;)
Sorry, typo ...
[]'s

[Aakshit Rajput]

If the extracting problem in the RAR file arises due to corruption issues then you can fix that tool by using a third-party tool.
Get more info at - https://wordpress.semnaitik.com/how-to-open-rar-files-without-winzip/

[Pabst Blue Ribbon]

Post by Virus Guy
The file was about 10k. It's a small (about 50 kb) xml file. I used
winrar (offhand not sure what version I've got - there's no intuitive
way to see the version). I used the password option and also encrypted
the file name.
============
Your message was rejected by gmail-smtp-in.l.google.com for the
5.7.0 This message was blocked because its content presents a potential
5.7.0 security issue. Please visit
5.7.0 https://support.google.com/mail/?p=BlockedMessage to review our
5.7.0 message content and attachment content guidelines.
=============
So either
(a) gmail doesn't like password-protected rar files, or
(b) gmail does real-time file-cracking and looked inside the archive and
discovered an xml file and it has a policy of rejecting xml files as
attachments.

The latter is impossible. RAR format have quite good password protection
(unlike ZIP, for example.)

There is an option to not encrypt file names, only file content. If all
Google wants is to see file name and size it should work.

Post by Virus Guy
Comments?

If you merge JPEG and RAR files (JPEG first, RAR second) then resulting
file will be recognized as JPEG by most programs, but will be correctly
unpacked by RAR.