Hi, --- My two cents--- As we were playing a bit with some SSH versions we came across some interesting 'bugs'. I hope this is not a 'known' bug, but I wasn't able to find any documentation regarding this flaw. I'll show the test from SSH 2.4.0 -> 2.4.0 (non-commercial version) Making a telnetconnection to see the version: root@ws:~# telnet test 22 Trying 192.168.1.15... Connected to test. Escape character is '^]'. SSH-1.99-2.4.0 SSH Secure Shell (non-commercial) ^] telnet> q Connection closed. This is my SSH version: root@ws:~# ssh -V ssh: SSH Secure Shell 2.4.0 (non-commercial version) on i686-pc-linux-gnu Lets try to make a ssh connection for a non existing user: root@ws:~# ssh blaaaaa@test blaaaaa's password: warning: Authentication failed. Disconnected; connection lost (Connection closed.). Now I try it for a existing user: root@ws:~# ssh marco@test marco's password: marco's password: marco's password: warning: Authentication failed. Disconnected; no more authentication methods available (No further authentication methods available.). A clear difference in the output. Now lets try scp with a non existing user. root@ws:~# touch test.txt root@ws:~# scp test.txt blaaa@test:/home/blaaa blaaa@test's password: scp: warning: ssh2 client failed to authenticate. (or you have too old ssh2 installed, check with ssh2 -V) warning: Authentication failed. Disconnected; connection lost (Connection closed.). scp: warning: child process (ssh2) exited with code 1. And now with a existing user root@ws:~# scp test.txt marco@test:/home/marco marco@test's password: marco@test's password: marco@test's password: scp: warning: ssh2 client failed to authenticate. (or you have too old ssh2 installed, check with ssh2 -V) warning: Authentication failed. Disconnected; no more authentication methods available (No further authentication methods available.). scp: warning: child process (ssh2) exited with code 1. Again, a clear difference in the output. --- Christian Schwalm's two cents---- configuration: moderson: ssh 3.0.1 solaris8/sparc (ssh2) eldoc: ssh 2.4.0 solaris8/x86 (ssh1/ssh2) schwalm is a valid user, blaaaaa not. (add or remove some a´s in blaaaaa .. i didnt count them every time) bla.txt is a normal textfile containing some random chars. (bla in this case hehe) scp´ing with correct password works fine in all cases without any error msgs. now we do some 3.0.1 -> 2.4.0 # scp bla.txt blaaaaaa@eldoc:/tmp blaaaaaa@eldoc's password: scp: warning: ssh2 client failed to authenticate. (or you have too old ssh2 installed, check with ssh2 -V) warning: Authentication failed. Disconnected; connection lost (Connection closed.). scp: warning: child process (/usr/local/bin/ssh2) exited with code 1. # scp bla.txt schwalm@eldoc:/tmp schwalm@eldoc's password: schwalm@eldoc's password: schwalm@eldoc's password: warning: Authentication failed. Disconnected; no more authentication methods available (No further authentication methods available.). scp: warning: ssh2 client failed to authenticate. (or you have too old ssh2 installed, check with ssh2 -V) scp: warning: child process (/usr/local/bin/ssh2) exited with code 1. lets see what happens in case of 2.4.0 -> 3.0.1 # scp bla.txt blaaaaaa@moderson:/tmp blaaaaaa@moderson's password: blaaaaaa@moderson's password: blaaaaaa@moderson's password: warning: Authentication failed. Disconnected; no more authentication methods available (No further authentication methods available.). scp: warning: child process (ssh2) exited with code 1. # scp bla.txt schwalm@moderson:/tmp schwalm@moderson's password: schwalm@moderson's password: schwalm@moderson's password: warning: Authentication failed. Disconnected; no more authentication methods available (No further authentication methods available.). scp: warning: child process (ssh2) exited with code 1. No difference here. here we try some 3.0.1 -> 3.0.1 # scp bla.txt schwalm@moderson:/tmp schwalm@moderson's password: schwalm@moderson's password: schwalm@moderson's password: scp: warning: ssh2 client failed to authenticate. (or you have too old ssh2 installed, check with ssh2 -V) warning: Authentication failed. Disconnected; no more authentication methods available (No further authentication methods available.). scp: warning: child process (/usr/local/bin/ssh2) exited with code 1. # scp bla.txt blaaaaaa@moderson:/tmp blaaaaaa@moderson's password: blaaaaaa@moderson's password: blaaaaaa@moderson's password: warning: Authentication failed. Disconnected; no more authentication methods available (No further authentication methods available.). scp: warning: ssh2 client failed to authenticate. (or you have too old ssh2 installed, check with ssh2 -V) scp: warning: child process (/usr/local/bin/ssh2) exited with code 1. Also here a slight difference in the output (different order, tried several times) -- Christian `eldoc´ Schwalm schwalmATinformatikDOTuni-hannoverDOTde "dont make your programs userfriendly, make your users friendly" ----- With other words... usernames of ssh 2.4.0 (ssh+scp) and 3.0.1 (scp) are guessable ?!? keep me informed... grtz, Marco van Berkum -- GCC dpu s:--- a- C+++ US++++ P++ L+++ E---- W N o-- K w--- O- M-- V-- PS+++ PE-- Y+ PGP--- t--- 5 X R* tv++ b+++ DI-- D---- G++ e- h+ r y* +---------------------+------------------+-------------------+ | Marco van Berkum | MB17300-RIPE | Security Engineer | | http://ws.obit.nl | "Chernobyl used | Network Admin | | m.v.berkumat_private | Windows" | UNIX | +---------------------+------------------+-------------------+
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