SFTP ERROR - RSA key (1023 bits) is weaker than expected minimum (1024 bits)

Problem:

Many clients using SSIS Secure FTP Task reported following error when they switched to the new version.

Negotiation failed. The server's RSA key (1023 bits) is weaker than expected minimum (1024 bits).

The server's RSA key (1023 bits) is weaker than expected minimum (1024 bits).

Possible Cause:

Some utilities like PuTTYGen has a common bug which creates 1023 bits key. By default new version of  SSIS Secure FTP Task rejects weaker key. We enforce minimum 1024 RSA key size in the new version. Any key lower than that will be rejected. As of now, we don't have a setting to reduce minimum RSA key size but we may expose this in the future. Use Build v2.6.0 or older if you wish to allow weaker key.

Solution:

Here are possible solutions to fix this error.

1. Use newer version of ZappySys SSIS PowerPack (Higher than 2.7.8.11017) which exposes Minimum RSA Key Size Setting on Connection Manager UI. You can change Minimum RSA Key setting to 1023 or lower to allow weaker key.
2. If above is not possible because you like to stay with older version then try to update SFTP server with SSH Key with higher bits 2048 so it doesn't fail client side validation.

Contact Us

If you have more question(s) feel free to contact us via Live chat or email to [e-mail]

https://zappysys.com/support/