safest command-line (not GUI) program to view apache logs?

bcw · 12-02-2009, 02:38 AM

Quote:

[...] log files may contain information supplied directly by the client, without escaping. Therefore, it is possible for malicious clients to insert control-characters in the log files, so care must be taken in dealing with raw logs.

However, from Googling around, there seem to be no command-line (non-GUI) programs specifically for viewing possibly-malicious apache logs. Or am I wrong? Until now, I have been using less. Is that ok from a security standpoint?

business_kid · 12-02-2009, 03:35 AM

18Googol2 · 12-02-2009, 04:21 AM

'tail -f' seems to be better.

zhjim · 12-02-2009, 04:50 AM

tail -f will only show you the last 10 lines and all new lines coming in. But what if the information you are looking for is above the 10 lines?

(And don't be a smarass and answer with tail -n 20 -f

)

Web31337 · 12-02-2009, 05:36 AM

UNsafe:

Code:

php -r "include('/var/log/httpd/access.log');"

i guess all standard CLI tools would be OK.

Code:

tail -n 500 | less

is for viewing 500 last lines in a console with ability to scroll up and down.

unixfool · 12-02-2009, 07:00 AM

Quote:

Originally Posted by zhjim

tail -f will only show you the last 10 lines and all new lines coming in. But what if the information you are looking for is above the 10 lines?

(And don't be a smarass and answer with tail -n 20 -f

)

The man pages are your friend.

I use tail as such:

tail -f -n 100 /var/log/httpd/access_log

Quote:

-f The -f option causes tail to not stop when end of file is reached, but rather to wait for additional data to be appended to the input. The -f option is ignored if the standard input is a pipe, but not if it is a FIFO.

Quote:

-n number The location is number lines.

Quote:

The default starting location is "-n 10", or the last 10 lines of the input.

bcw · 12-03-2009, 11:35 PM

thanks for the help, everyone.

Quote:

Originally Posted by Web31337

UNsafe:

Code:

php -r "include('/var/log/httpd/access.log');"

i guess all standard CLI tools would be OK.

yeah, i can see how that could be a problem. so basically, don't feed the logs into any executable context, right?

i was actually worried more about someone using shell control characters to trick the shell itself into executing another (arbitrary) command. but now that i think about it, unredirected output from programs the shell executes are just sent to the shell's own stdout/stderr, and have no chance to influence the shell's commands (stdin). isn't that right?