[Bug 533352] Re: [LUCID] We need "limit" Upstart-ed ssh respawning
Fumihito YOSHIDA
hito at kugutsu.org
Sat Mar 6 16:21:12 GMT 2010
** Description changed:
ssh is now handling by upstart native jobs(with /etc/init/ssh.conf
configs), and "respawn" stanza. This is great works. But this behavior
is not familiar for security paranoid.
Scenario:
- - sshd is enougth to berief, but this is not perfect. In future, if we have got vuln for exploiting sshd, that can "randomly" type atacks (e.g.: buffer overflow, it is exploitable with probabilistic atacks, like brute force.).
- - endless respawning is weaken for these "memory address brute force" atacks.
+ - sshd is enougth to berief, but this is not perfect. In future, if we have got vuln for exploiting sshd, that can "randomly" type atacks (e.g.: buffer overflow, it is exploitable with probabilistic atacks, like brute force.).
+ - endless respawning is weaken for these "memory address brute force" atacks.
- IMHO, when using "respawn" stanza, it needs something "limit" stanza (e.g.: respawn limit 60 30) or any other way ( e.g.: MAC by AppArmor). limitation by "limit" can mitigates(atack speed limitation) probabilistic atacks. This limitation provides potential over-limit DoS, but unlimited respawning is dangerous.
- # May be, we have to improvement upstart respawn stanza, like "respawn delay" feature...
+ IMHO, when using "respawn" stanza, it needs something "limit" stanza (e.g.: respawn limit 60 30)
+ or any other way ( e.g.: MAC by AppArmor).
- ....Yes, this wish is not only ssh services. But ssh is most popular +
- internet accessible services.
+ limitation by "limit" can mitigates(atack speed limitation) probabilistic atacks.
+ This limitation provides potential over-limit DoS, but unlimited respawning is dangerous.
+
+ # May be, we have to improvement upstart respawn stanza, like "respawn delay"
+ # feature...(see https://bugs.launchpad.net/upstart/+bug/252997)
+
+ ....Yes, this wish is not only ssh services. But ssh is most popular + internet accessible services.
+ In general cases, administrator use "ufw limit ssh" settings. Its not hazardous.
--
[LUCID] We need "limit" Upstart-ed ssh respawning
https://bugs.launchpad.net/bugs/533352
You received this bug notification because you are a member of Ubuntu
Server Team, which is subscribed to openssh in ubuntu.
More information about the Ubuntu-server-bugs
mailing list