Corrupted MAC on input

[zhanglc]

Prerequisites

• Write a descriptive title.
• Make sure you are able to repro it on the latest version
• Search the existing issues.

Steps to reproduce

ssh -vvv root@x.x.x.x

sshd_config:

#       $OpenBSD: sshd_config,v 1.103 2018/04/09 20:41:22 tj Exp $

Include /etc/ssh/sshd_config.d/*.conf

# Change to yes to enable challenge-response passwords (beware issues with
# some PAM modules and threads)
ChallengeResponseAuthentication no

# Set this to 'yes' to enable PAM authentication, account processing,
# and session processing. If this is enabled, PAM authentication will
# be allowed through the ChallengeResponseAuthentication and
# PasswordAuthentication.  Depending on your PAM configuration,
# PAM authentication via ChallengeResponseAuthentication may bypass
# the setting of "PermitRootLogin without-password".
# If you just want the PAM account and session checks to run without
# PAM authentication, then enable this but set PasswordAuthentication
# and ChallengeResponseAuthentication to 'no'.
UsePAM yes

X11Forwarding yes
#X11DisplayOffset 10
#X11UseLocalhost yes
#PermitTTY yes
PrintMotd no

Banner /etc/ssh_login.warn

AcceptEnv LANG LC_*

# override default of no subsystems
Subsystem       sftp    /usr/lib/openssh/sftp-server

sshd_algorithms.conf

MACs umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com
kexAlgorithms curve25519-sha256,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521
Ciphers aes128-ctr,aes192-ctr,aes256-ctr
CASignatureAlgorithms ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
HostbasedAcceptedKeyTypes ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com
HostKeyAlgorithms ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,sk-ecdsa-sha2-nistp256-cert-v01@openssh.com,ssh-ed25519-cert-v01@openssh.com,sk-ssh-ed25519-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,sk-ecdsa-sha2-nistp256@openssh.com,ssh-ed25519,sk-ssh-ed25519@openssh.com
PubkeyAcceptedKeyTypes ecdsa-sha2-nistp256,ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com

ssh output:

OpenSSH_for_Windows_9.2p1, LibreSSL 3.7.2
debug3: Failed to open file:C:\\XXX/.ssh/config error:2
debug3: Failed to open file:C:/ProgramData/ssh/ssh_config error:2
debug2: resolve_canonicalize: hostname x.x.x.x is address
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts' -> 'C:\\XXX/.ssh/known_hosts'
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts2' -> 'C:\\XXX/.ssh/known_hosts2'
debug3: ssh_connect_direct: entering
debug1: Connecting to x.x.x.x [x.x.x.x] port 22.
debug1: Connection established.
debug1: identity file C:\\XXX/.ssh/id_rsa type 0
debug3: Failed to open file:C:\\XXX/.ssh/id_rsa-cert error:2
debug3: Failed to open file:C:\\XXX/.ssh/id_rsa-cert.pub error:2
debug3: failed to open file:C:\\XXX/.ssh/id_rsa-cert error:2
debug1: identity file C:\\XXX/.ssh/id_rsa-cert type -1
debug3: Failed to open file:C:\\XXX/.ssh/id_ecdsa error:2
debug3: Failed to open file:C:\\XXX/.ssh/id_ecdsa.pub error:2
debug3: failed to open file:C:\\XXX/.ssh/id_ecdsa error:2
debug1: identity file C:\\XXX/.ssh/id_ecdsa type -1
debug3: Failed to open file:C:\\XXX/.ssh/id_ecdsa-cert error:2
debug3: Failed to open file:C:\\XXX/.ssh/id_ecdsa-cert.pub error:2
debug3: failed to open file:C:\\XXX/.ssh/id_ecdsa-cert error:2
debug1: identity file C:\\XXX/.ssh/id_ecdsa-cert type -1
debug3: Failed to open file:C:\\XXX/.ssh/id_ecdsa_sk error:2
debug3: Failed to open file:C:\\XXX/.ssh/id_ecdsa_sk.pub error:2
debug3: failed to open file:C:\\XXX/.ssh/id_ecdsa_sk error:2
debug1: identity file C:\\XXX/.ssh/id_ecdsa_sk type -1
debug3: Failed to open file:C:\\XXX/.ssh/id_ecdsa_sk-cert error:2
debug3: Failed to open file:C:\\XXX/.ssh/id_ecdsa_sk-cert.pub error:2
debug3: failed to open file:C:\\XXX/.ssh/id_ecdsa_sk-cert error:2
debug1: identity file C:\\XXX/.ssh/id_ecdsa_sk-cert type -1
debug3: Failed to open file:C:\\XXX/.ssh/id_ed25519 error:2
debug3: Failed to open file:C:\\XXX/.ssh/id_ed25519.pub error:2
debug3: failed to open file:C:\\XXX/.ssh/id_ed25519 error:2
debug1: identity file C:\\XXX/.ssh/id_ed25519 type -1
debug3: Failed to open file:C:\\XXX/.ssh/id_ed25519-cert error:2
debug3: Failed to open file:C:\\XXX/.ssh/id_ed25519-cert.pub error:2
debug3: failed to open file:C:\\XXX/.ssh/id_ed25519-cert error:2
debug1: identity file C:\\XXX/.ssh/id_ed25519-cert type -1
debug3: Failed to open file:C:\\XXX/.ssh/id_ed25519_sk error:2
debug3: Failed to open file:C:\\XXX/.ssh/id_ed25519_sk.pub error:2
debug3: failed to open file:C:\\XXX/.ssh/id_ed25519_sk error:2
debug1: identity file C:\\XXX/.ssh/id_ed25519_sk type -1
debug3: Failed to open file:C:\\XXX/.ssh/id_ed25519_sk-cert error:2
debug3: Failed to open file:C:\\XXX/.ssh/id_ed25519_sk-cert.pub error:2
debug3: failed to open file:C:\\XXX/.ssh/id_ed25519_sk-cert error:2
debug1: identity file C:\\XXX/.ssh/id_ed25519_sk-cert type -1
debug3: Failed to open file:C:\\XXX/.ssh/id_xmss error:2
debug3: Failed to open file:C:\\XXX/.ssh/id_xmss.pub error:2
debug3: failed to open file:C:\\XXX/.ssh/id_xmss error:2
debug1: identity file C:\\XXX/.ssh/id_xmss type -1
debug3: Failed to open file:C:\\XXX/.ssh/id_xmss-cert error:2
debug3: Failed to open file:C:\\XXX/.ssh/id_xmss-cert.pub error:2
debug3: failed to open file:C:\\XXX/.ssh/id_xmss-cert error:2
debug1: identity file C:\\XXX/.ssh/id_xmss-cert type -1
debug3: Failed to open file:C:\\XXX/.ssh/id_dsa error:2
debug3: Failed to open file:C:\\XXX/.ssh/id_dsa.pub error:2
debug3: failed to open file:C:\\XXX/.ssh/id_dsa error:2
debug1: identity file C:\\XXX/.ssh/id_dsa type -1
debug3: Failed to open file:C:\\XXX/.ssh/id_dsa-cert error:2
debug3: Failed to open file:C:\\XXX/.ssh/id_dsa-cert.pub error:2
debug3: failed to open file:C:\\XXX/.ssh/id_dsa-cert error:2
debug1: identity file C:\\XXX/.ssh/id_dsa-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_for_Windows_9.2
debug1: Remote protocol version 2.0, remote software version OpenSSH_8.4p1 Debian-5
debug1: compat_banner: match: OpenSSH_8.4p1 Debian-5 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to x.x.x.x:22 as 'secur1ty'
debug3: record_hostkey: found key type ECDSA in file C:\\XXX/.ssh/known_hosts:5
debug3: load_hostkeys_file: loaded 1 keys from x.x.x.x
debug3: Failed to open file:C:\\XXX/.ssh/known_hosts2 error:2
debug1: load_hostkeys: fopen C:\\XXX/.ssh/known_hosts2: No such file or directory
debug3: Failed to open file:C:/ProgramData/ssh/ssh_known_hosts error:2
debug1: load_hostkeys: fopen __PROGRAMDATA__\\ssh/ssh_known_hosts: No such file or directory
debug3: Failed to open file:C:/ProgramData/ssh/ssh_known_hosts2 error:2
debug1: load_hostkeys: fopen __PROGRAMDATA__\\ssh/ssh_known_hosts2: No such file or directory
debug3: order_hostkeyalgs: prefer hostkeyalgs: ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp256
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,ext-info-c
debug2: host key algorithms: ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp256,ssh-ed25519-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,sk-ssh-ed25519-cert-v01@openssh.com,sk-ecdsa-sha2-nistp256-cert-v01@openssh.com,rsa-sha2-512-cert-v01@openssh.com,rsa-sha2-256-cert-v01@openssh.com,ssh-ed25519,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,sk-ssh-ed25519@openssh.com,sk-ecdsa-sha2-nistp256@openssh.com,rsa-sha2-512,rsa-sha2-256
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com,zlib
debug2: compression stoc: none,zlib@openssh.com,zlib
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521
debug2: host key algorithms: ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: aes128-ctr,aes192-ctr,aes256-ctr
debug2: ciphers stoc: aes128-ctr,aes192-ctr,aes256-ctr
debug2: MACs ctos: umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com
debug2: MACs stoc: umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com
debug2: compression ctos: none,zlib@openssh.com
debug2: compression stoc: none,zlib@openssh.com
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: aes128-ctr MAC: umac-128-etm@openssh.com compression: none
debug1: kex: client->server cipher: aes128-ctr MAC: umac-128-etm@openssh.com compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: SSH2_MSG_KEX_ECDH_REPLY received
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:JQXEGbJuKdCsTF0b0Jksdzb8ipQYBD5i5toaqGnvKII
debug3: record_hostkey: found key type ECDSA in file C:\\XXX/.ssh/known_hosts:5
debug3: load_hostkeys_file: loaded 1 keys from x.x.x.x
debug3: Failed to open file:C:\\XXX/.ssh/known_hosts2 error:2
debug1: load_hostkeys: fopen C:\\XXX/.ssh/known_hosts2: No such file or directory
debug3: Failed to open file:C:/ProgramData/ssh/ssh_known_hosts error:2
debug1: load_hostkeys: fopen __PROGRAMDATA__\\ssh/ssh_known_hosts: No such file or directory
debug3: Failed to open file:C:/ProgramData/ssh/ssh_known_hosts2 error:2
debug1: load_hostkeys: fopen __PROGRAMDATA__\\ssh/ssh_known_hosts2: No such file or directory
debug1: Host 'x.x.x.x' is known and matches the ECDSA host key.
debug1: Found key in C:\\XXX/.ssh/known_hosts:5
debug3: send packet: type 21
debug2: ssh_set_newkeys: mode 1
debug1: rekey out after 4294967296 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: ssh_set_newkeys: mode 0
debug1: rekey in after 4294967296 blocks
debug3: ssh_get_authentication_socket_path: path '\\\\.\\pipe\\openssh-ssh-agent'
debug2: get_agent_identities: ssh_agent_bind_hostkey: invalid format
debug1: get_agent_identities: ssh_fetch_identitylist: agent contains no identities
debug1: Will attempt key: C:\\XXX/.ssh/id_rsa RSA SHA256:4HFB+dv5MV9gamIRyXzVFpiGnxyG9buP72FRX/CfGzA
debug1: Will attempt key: C:\\XXX/.ssh/id_ecdsa
debug1: Will attempt key: C:\\XXX/.ssh/id_ecdsa_sk
debug1: Will attempt key: C:\\XXX/.ssh/id_ed25519
debug1: Will attempt key: C:\\XXX/.ssh/id_ed25519_sk
debug1: Will attempt key: C:\\XXX/.ssh/id_xmss
debug1: Will attempt key: C:\\XXX/.ssh/id_dsa
debug2: pubkey_prepare: done
debug3: send packet: type 5
Corrupted MAC on input.
ssh_dispatch_run_fatal: Connection to x.x.x.x port 22: message authentication code incorrect

Expected behavior

ssh login success

Actual behavior

Corrupted MAC on input.
ssh_dispatch_run_fatal: Connection to x.x.x.x port 22: message authentication code incorrect

Error details

No response

Environment data

Name                           Value
----                           -----
PSVersion                      5.1.19041.2673
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.19041.2673
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

Version

OpenSSH_for_Windows_9.2p1, LibreSSL 3.7.2

Visuals

No response

[tgauth]

Based on https://serverfault.com/questions/994646/ssh-on-windows-corrupted-mac-on-input, run: ssh -Q mac then add -m <one of the macs from the output of ssh-Q mac> to the ssh -vvv root@x.x.x.x command

[zhanglc]

Client and Server had negotiated the mac algorithm, So the way you say it is not feasible @tgauth

debug1: kex: server->client cipher: aes128-ctr MAC: umac-128-etm@openssh.com compression: none
debug1: kex: client->server cipher: aes128-ctr MAC: umac-128-etm@openssh.com compression: none

[tgauth]

Could you still try the -m option explicitly? The error message is the same as in the link above, and that was the solution.

hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com are also listed in sshd_algorithms.conf, could you remove umac-128-etm@openssh.com and see if one of the other MACs works?

Also, have you tried updating the server from OpenSSH 8.4 to a more current version?
Or have you seen this issue with any other SSH clients aside from Windows OpenSSH 9.2?

[zhanglc]

@tgauth It works when use ssh -m hmac-sha2-256-etm@openssh.com xxx@x.x.x.x, thanks a lot .

By the way , why the algo umac-128-etm@openssh.com not work ? different implament between OpenSSH 8.4 and OpenSSH_for_Windows_9.2p1?

[tgauth]

Great!

It seems like this might be related to the crypto libraries used with each OpenSSH and their implementations of umac-128-etm@openssh.com - see #1359. Do you know if the server has FIPS enabled?

[ket000]

I have installed the latest version OpenSSH_for_Windows_9.5p1, LibreSSL 3.8.2 and issue is still there when below macs are used.

umac-128-etm@openssh.com
umac-128@openssh.com

To workaround, I have added the below to my %USERPROFILE%/.ssh/config file

Host *
MACs=hmac-sha2-256,hmac-sha2-512,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com

or use the below command line option wen invoking ssh

ssh -oMACs=hmac-sha2-256,hmac-sha2-512,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com username@server.com

This has resolved the issue. Same works fine from putty, mac, Red Hat Linux 8 and 7 without any issues, so issue seems to be with Windows OpenSSH client. Hopefully it gets fixed eventually so no workaround is needed.

[maertendMSFT]

We believe that the issue is coming from LibreSSL, specifically: libressl/portable#603. We will see if we can get any traction on the thread.

[ket000]

Thanks for the update. Hopefully libressl version for windows can be fixed. I noticed this issue when i disabled chacha20-poly1305@openssh.com encryption algorithm on linux 8.9 server and windows / linux decided to use umac-128-etm@openssh.com to mitigate terrapin attack.

[ByteEnable]

I have experienced the same issue as @ket000 .

Corrupted MAC on input.
ssh_dispatch_run_fatal: Connection to XXX.XXX.XXX.XXX port 22: message authentication code incorrect

Version:
OpenSSH_for_Windows_8.6p1, LibreSSL 3.4.3

Workaround:
ssh -m hmac-sha2-512 user@host

[pzxocs]

Reporting the same issue.
Corrupted MAC on input.
ssh_dispatch_run_fatal: Connection to * port 22: message authentication code incorrect

ssh -V on client:
OpenSSH_for_Windows_8.1p1, LibreSSL 3.0.2
server:
OpenSSH_8.0p1, OpenSSL 1.1.1k FIPS 25 Mar 2021

@ket000 solution worked for me

[bsteinb]

It seems to be confirmed now that the MAC algorithms umac-128-etm@openssh.com and umac-128@openssh.com are not working at the moment. Instead of relying on user configuration to work around the issue, would it make sense to push a new release that completely disables these algorithms?