Main page | Install | ttyreplay(1) | rpldev(4) | rpl(5) | ttyrpld(7) | rplctl(8) | rpld(8) | Netlogging | Support
| Description > |
ttyrpld is a Kernel-rooted/-based keylogger and screenlogger for Linux 2.x with a real-time and tail-follow log analyzer. It supports any tty type (vc, bsd/unix98 pty (xterm/ssh), serial, isdn, etc.). Being implemented within the Kernel makes it incircumventable for the default user. Another benefit is that it runs with no overhead if the user-space logging daemon is not active. |
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| Categorization (SF-style) > |
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| Technical Aspects > |
... which cause it to differ from existing solutions: Most other solutions deploy the logging completely in userspace and make it dependent on the user to activate the logging. Definitely, an intruder does not start e.g. /usr/bin/script voluntarily. I have only seen two other kernel-based loggers. One of them is sadly outdated, the other is more complex (i.e. queries keyboard driver instead of tty lines) and only allows network logging, yet aims to be more hidden. To sum it up, there exist only very few solutions to which I could compare. You can get a listing of what tty drivers the Kernel has currently loaded by looking at /proc/tty/drivers. Every kind is supported, giving that it uses the tty routines rather than just introducing itself to /tty/drivers. So to say, /dev/console is usually not caught. For one, because it is only activate before the normal boot process runs, second, it is not used often by userspace, and third, it does not seem to generate any events. In short, it logs what you need. |
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| Components > |
This kit (ttyrpld) consists of four components: kpatch: The Kernel patch adds a few lines to provide the rpldev extension hooks, which (any) module can then get onto. The system was not directly written for black-hats who want to leave as little traces as possible, keep in mind. :-) rpldev: The Kernel module is responsible for grabbing the data off the tty line and providing a character device for the user-space logging daemon. Data grabbed of the tty is directly passed to the overlying daemons, so with the correct terminal settings you can get a 1:1 replay. rpld: Having received the captured data, the logging daemon can store them in any format and/or facility, with or without compression, just as it likes, for this happens in user-space and thus you have all the fluffy libraries available. (That would not be the case from Kernel space.) ttyreplay: real-time log analyzer. Think of it like a video player. | ||||||||||||||||||
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| by Jan Engelhardt | * |