I have make an example as below. The password（mingps）is the shell variable. When execute the shell script, in the mean while, execute command "ps -ef", I found the result of "ps" showed the password(mingps). For security reason, I don't want to show the password when execute command "ps -ef". So how to hide it? Thanks in advance.
#!/bin/sh
MalbanIP="XXX.XXX.XXX.XXX"
MalbanLogin="ming"
MalbanPwd="mingps"
MalbanCmd="netstat"
firstTime="true"
/usr/bin/expect <<EOF
set timeout 10
log_user 0
spawn /usr/bin/ssh $MalbanIP -l $MalbanLogin
expect {
-nocase "continue connecting (yes/no)?" {
send "yes\r"
expect "password:" {
send "$MalbanPwd\r"; set firstTime "false"; exp_continue
}
}
"password" {
if {$firstTime == "true"} {
send "$MalbanPwd\r"; set firstTime "false"
} else {
log_user 1; puts stdout "password is wrong"; log_user 0;
exit 1
}
}
}
expect "0-0-3"
log_user 1
send "$MalbanCmd \r"
set results \$expect_out(buffer)
expect "0-0-3" { send "exit\r" }
expect eof
EOF
exit 0
The best way is to switch to using RSA keys to log in, as this will enable you to significantly strengthen your overall system security substantially. With that, you can probably avoid using Expect entirely.
However, if you can't do that, the key to fixing things is to not pass it as either an argument or an environment variable (since ps can see both with the right options). Instead, you pass the password by writing it into a file and giving the name of that file to the Expect script. The file needs to be in a directory that only the current user can read; chmod go-rx will help there.
MalbanPwdFile=/home/malban/.securedDirectory/examplefile.txt
# Put this just before the spawn
set f [open $MalbanPwdFile]
set MalbanPwd [gets $f]
close $f
You might also need to put a backslash in front of the use of $MalbanPwd so that it doesn't get substituted by the shell script part too early.
Or you could stop using that shell wrapper and do everything directly in Tcl/Expect.
#!/usr/bin/expect
set MalbanIP "XXX.XXX.XXX.XXX"
set MalbanLogin "ming"
set MalbanPwd "mingps"
set MalbanCmd "netstat"
set firstTime true
set timeout 10
log_user 0
spawn /usr/bin/ssh $MalbanIP -l $MalbanLogin
expect {
-nocase "continue connecting (yes/no)?" {
send "yes\r"
expect "password:" {
send "$MalbanPwd\r"
set firstTime false
exp_continue
}
}
"password" {
if {$firstTime} {
send "$MalbanPwd\r"
set firstTime false
} else {
log_user 1
puts stdout "password is wrong"
log_user 0
exit 1
}
}
}
expect "0-0-3"
log_user 1
send "$MalbanCmd \r"
set results \$expect_out(buffer)
expect "0-0-3" { send "exit\r" }
expect eof
I suspect that this last option will work best for you in the longer term. It's definitely the simplest one (other than switching to RSA keys, which is what I've got deployed on my own infrastructure) and I think it is going to avoid some subtle bugs that you've got in your current code (due to substitution of variables at the wrong time).
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