#BITVISE SSH CLIENT 6.40 GENERATOR#
#BITVISE SSH CLIENT 6.40 MANUAL#
#BITVISE SSH CLIENT 6.40 SOFTWARE#
#BITVISE SSH CLIENT 6.40 WINDOWS#

Understanding and replacing Bitvise SSH Server host keys Upgrading DSA client authentication keys We recommend the following page for more information: Replacing a host key is a non-trivial process. If you find that your SSH Server uses a DSA host key - be it standard or non-standard - we recommend replacing it with a 3072-bit RSA key, or with an ECDSA key. Run the script against the new-version installation. Import settings on the new-version installation. It does not need to be activated or started.Įxport settings from the older-version installation. Make a temporary new-version installation. If you wish to use this script before upgrading a production installation from an older version, you will need to: To use the above script, the SSH Server version where it is run must be already upgraded.

If there are multiple SSH Server instances installed simultaneously, you may need to alter the script so it invokes $cfg.SetInstance to select the intended instance. The script needs to be run in an elevated, administrative PowerShell or Command Prompt window, on the computer where the SSH Server is installed. If you have an SSH Server configuration with a large number of accounts, you can use the following PowerShell script to check your settings automatically:

#BITVISE SSH CLIENT 6.40 WINDOWS#

User authentication keys in each virtual or Windows account settings entry. SSH Server host keypairs, under Manage host keys in the SSH Server Control Panel. If you have an SSH Server configuration with a small number of accounts, then look for non-standard DSA keys in the following locations:

#BITVISE SSH CLIENT 6.40 MANUAL#

You will need to take manual steps to determine the types of such host keys.Ĭhecking for DSA keys in Bitvise SSH Server parameter, or host keys that are not stored at all, whose fingerprints are passed using -hostKeyFp=. Your usage may rely on DSA host keys stored in files and passed using the -hostKeyFile=.

You may need to import such files using the SSH Client's Client key manager to verify the key type they contain. Your usage may rely on DSA client authentication keys stored in files and passed using the -keypairFile=. In addition, if you are using command line clients such as sftpc, stnlc, stermc, sexec: However, those versions also no longer support non-standard DSA keys, so such keys would not be stored there. Newer SSH Client versions additionally support storing host keys and client authentication keypairs in individual profiles. In the graphical SSH Client, check the following locations to find whether your use relies on DSA keys:Ĭheck the Host key manager interface for any DSA host keys saved for servers you connect to.Ĭheck the Client key manager interface for any DSA keys used for client authentication. Checking for DSA keys in Bitvise SSH Client Large RSA keys are likely to be supported in all environments that support large DSA keys. We recommend that any use of DSA keys, non-standard or standard, is replaced with 3072-bit RSA keys or with ECDSA keys. The main reason DSA was designed is because RSA was encumbered with patents. In newer SSH implementations, RSA keys can use SHA-2 hashing. Any DSA keys used in SSH therefore must use SHA-1, which is no longer recommended for use in signing, and is in some places prohibited. The IETF standards body has decided not to pursue a standard to use DSA keys in SSH with SHA-2 hashing. due to a bad random seed or a virtual machine restore, the private key can be extracted from only these two signatures. If the same random parameter is ever used to sign two messages, e.g.

#BITVISE SSH CLIENT 6.40 GENERATOR#

If the random number generator is flawed even in a minor way, the private key can be extracted from the signatures. The following is true in general for DSA keys in SSH:ĭSA signatures are highly sensitive to the quality of randomness used in signing. Such keys have a deceptive size and are less secure than intended.

#BITVISE SSH CLIENT 6.40 SOFTWARE#

Keys generated by such software are likely to be no stronger than 1024-bit DSA keys.

Software derived from these old versions of OpenSSH is still in use on some platforms. The keys that are used in practice are incompatible with the NIST standard for large DSA keys.Īt a time when these keys were supported by OpenSSH (they have not been for a decade), OpenSSH incorrectly generated them without enlarging the subgroup size compared to 1024-bit keys. The following are some problems with non-standard (larger than 1024-bit) DSA keys in SSH: In addition, recent versions of OpenSSH have also removed support for DSA completely.īefore continuing, we recommend that you are familiar with Public keys in SSH. Versions 8.xx - 9.xx support these keys, but disable them by default. These are DSA keys larger than 1024 bits. Versions 7.xx do not support non-standard DSA keys. Versions 7.xx - 9.xx support standard (1024-bit) DSA keys, but disable them by default. A noticeable pain for a proportion of users of Bitvise software versions 6.xx and older is that:

Bitvise ssh client 6.40