habibzain Just husband, father and enthusiastic men about System Administration. Love to write short article about it. Perhaps can help and be useful for others.

Amavis Blocking Email with encrypted zip

1 min read

Amavis Blocking Email with encrypted zip

Hi Dude, today I will write a story about handling spam emails that have an encrypted zip file attachment. This article about simple tips for amavis block encrypted zip. Lots of incoming emails, with impersonate email features and looks like a true email sender.

amavis block encrypted zip

So the end user receives a lot of email with an encrypted zip attachment email pattern. Amavisd does know its protected, the subject line gets changed to ***UNCHECKED ***.

At first, i am install zip package for scan archive file in email messages.

yum -y install gzip unzip zip

Read more: Install Winrar On Linux From Source

And then edit, amavisd.conf. Just add UNDECIPHERABLE to the list of banned file names in amavisd.conf and all encrypted zips will be blocked.

root@server# vim /etc/amavisd/amavisd.conf

$banned_filename_re = new_RE(
   qr'^UNDECIPHERABLE$',  # is or contains any undecipherable components
);

But this method has a global impact and is false positive. If there is a correct email that has a zip file attachment, the passwordd file will also be blocked.

If we send email to server that implemented, we will get error like this.

Our content checker found
 banned name: 2022-07-06_1311.xls,UNDECIPHERABLE

That is amavis block encrypted zip. The last, how to bypass or whitelist email valid but rejected impact from this rule? See in this Article How to Bypass amavisd Filter Check. for certain purposes, we can bypass to allow incoming email which is blocked by amavis. We must be careful in determining this rule, because there is no more filtering.

It’s a good idea to use a paid anti-spam and anti-virus service, or a cloud-based enterprise. Sysadmins not always think about email, they can focus more on other system improvements besides email.

See also  Install Unbound Ubuntu 20.04/22.04 with Compile

Let's Buy Me Coffee.

Buy Me a Coffee at ko-fi.com

https://saweria.co/habibzain
https://ko-fi.com/habibzain
habibzain Just husband, father and enthusiastic men about System Administration. Love to write short article about it. Perhaps can help and be useful for others.

Easy Create Laravel Project with Composer

Requirement Laravel, a popular PHP framework, is renowned for its elegant syntax and robust features, making it a top choice for web developers. One...
habibzain
1 min read

Virtualbox Change Storage Size

Changing the storage size of a virtual machine in VirtualBox involves a few steps. Here’s a general guide. Backup your Virtual Machine (VM) Before...
habibzain
35 sec read

Easy Setup Logrotate Nginx Ubuntu

Log rotation is an important aspect of managing log files on a Linux system, including those generated by Nginx. Logrotate is a utility that...
habibzain
1 min read

Leave a Reply

Your email address will not be published. Required fields are marked *

Never miss good article from us, get weekly updates in your inbox