plink.exe is too old to connect to servers configured to only accept modern ciphers

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    • Type: Bug
    • Resolution: Fixed
    • Priority: Highest
    • 2.4.0-beta-0
    • Affects Version/s: 1.8.2.11, 1.9.3-beta-1, 1.10.0-alpha-1
    • Component/s: None
    • Severity 3 - Minor

      When using SourceTree with PuTTY against a Git server only accepting modern HMACs (for example hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-ripemd160-etm@openssh.com,umac-128-etm@openssh.com,hmac-ripemd160,uma-128@openssh.com,hmac-sha2-512,hmac-sha2-256) the communication fails with

      We claim version: SSH-2.0-PuTTY_Local:_Apr_16_2013_12:55:41
Server version: SSH-2.0-OpenSSH_6.7p1 Debian-5+deb8u2
Using SSH protocol version 2
Doing Diffie-Hellman group exchange
Server unexpectedly closed network connection
FATAL ERROR: Server unexpectedly closed network connection

      In the server log one can see:

      sshd[75215]: fatal: no matching mac found: client hmac-sha1,hmac-sha1-96,hmac-md5 server umac-64-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-ripemd160-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,hmac-ripemd160,umac-128@openssh.com [preauth]

      The root cause for this problem is that the plink in the SourceTree distribution is ~3 years old. Updating the included PuTTY tools (plink, pagent and puttygen) would also fix some security bugs found in PuTTY in recent years and would update puttygen to generate 2048-bit RSA keys by default.

      PS: You might even consider using TortoiseGitPlink, which is patched to show host key prompts as Windows dialogs...

            Assignee:
            Unassigned
            Reporter:
            Tobias Gruetzmacher
            Votes:
            3 Vote for this issue
            Watchers:
            6 Start watching this issue

              Created:
              Updated:
              Resolved: