tahoe-lafs/trac-2024-07-25
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PyCrypto 2.4.1 is vulnerable to timing attacks 

[Imported from Trac: page SftpFrontend, version 87]
daira 2013-10-17 14:40:34 +00:00
parent 3a049d9a5c
commit 0b55961754
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SftpFrontend.md

@ -5,7 +5,7 @@ See [docs/frontends/FTP-and-SFTP.rst (.txt in releases before v1.8.1)](http://ta
# Security
The security of the connection between the SFTP client and gateway is dependent on the PyCrypto library, which has not been reviewed to the same extent as the pycryptopp library that we use elsewhere in Tahoe-LAFS. In particular, the AES implementation in PyCrypto might be vulnerable to timing attacks and the RSA implementation in PyCrypto up to and including PyCrypto v2.3 is vulnerable to timing attacks. Either of these could potentially, depending on the situation, allow a remote attacker to break the encryption protecting the SFTP connection between your SFTP client and the Tahoe-LAFS gateway process that is acting as SFTP server. Therefore we do not recommend that you rely on the confidentiality or authentication provided by this SSH connection in the current release.
The security of the connection between the SFTP client and gateway is dependent on the PyCrypto library, which has not been reviewed to the same extent as the pycryptopp library that we use elsewhere in Tahoe-LAFS. In particular, the AES implementation in PyCrypto might be vulnerable to timing attacks and the RSA implementation in PyCrypto up to and including PyCrypto v2.4.1 is vulnerable to timing attacks. Either of these could potentially, depending on the situation, allow a remote attacker to break the encryption protecting the SFTP connection between your SFTP client and the Tahoe-LAFS gateway process that is acting as SFTP server. Therefore we do not recommend that you rely on the confidentiality or authentication provided by this SSH connection in the current release.
In practice, that means you can run the Tahoe-LAFS gateway locally on the same machine as your SFTP client (which is a good, efficient, and secure solution), or tunnel your SFTP connection over another secure connection such as ssh tunnel or VPN, or else just accept the risk that someone could snoop on the data that you are sending and receiving over the SFTP connection.