Oi! *Nix admin, get patching

The Register ^ | September 18, 2003 | John Leyden

[FourPeas]

Oi! *Nix admin, get patching By John Leyden, The Register Sep 18 2003 5:58AM It's become a busy week for *Nix sysadmins with the release of patches over the last few days to resolve vulnerabilities with popular applications including Sendmail, openSSH and DB2. Those *Nix techies enjoying a sense of schadenfreude as their Windows sysadmin colleagues toiled to defend Windows systems against Blaster, Sobig, Nachi et all over the last month now have some work on their hands. -------------------------------------------------------------------------------- First, users of the popular OpenSSH security package need to upgrade to version 3.7.1 because of a buffer overflow flaw. The vulnerability could allow an attacker to corrupt heap memory and trigger a denial-of-service condition. "It may also be possible for an attacker to execute arbitrary code," security clearing house CERT warns. CERT's advisory contains a links to patches from software distros that contain OpenSSH code and to OpenSSH project's own update. An OpenSSH advisory provides a detailed technical explanation of the flaw. OpenSSH is a free version of the SSH (Secure Shell) communications suite and is used as a secure replacement for protocols such as Telnet, Rlogin, RSH, and FTP. SSH Communications Security products have different code base to OpenSSH and are therefore immune to the flaw. -------------------------------------------------------------------------------- Moving along, the ubiquitous Sendmail email server package is also affected by a buffer overflow vulnerability. The Sendmail Consortium urges all users to upgrade to Sendmail 8.12.10 because of the flaw in address parsing, which it defines as critical. Credit for discovering the vulnerability goes to security researcher Michal Zalewski. Although no exploit currently exists, this issue is locally exploitable and may also be remotely exploitable, a Red Hat advisory warns. Red Hat bundles the application in its distro warns. Sendmail 8.12.10 also fixes a potential buffer overflow in rule set parsing. Patches are available from the Sendmail Consortium or Linux distros. Those not running the open source version of Sendmail are advised to check with their vendors for a patch. -------------------------------------------------------------------------------- Finally there's vulnerability with the version 7 of the Linux edition of IBM's DB2 database software. IBM has issued a patch, in advance of updating its technical support page with more details. Boston security company Core Security Technologies, which discovered the problem, is expected to release an advisory later today. The flaw could allow an attacker to get "root" privileges to a DB2 database, C/Net reports. Once again the vulnerability (surprise, surprise) again stems from a buffer overflow flaw. ®

[ancient_geezer]

BBBBUT, only Windows guys get virus er virii? Right!!

LOL

[Myrddin]

Hacking *nix boxes was popular a long time before Windows was invented. Breaking "root" is a favorite activity. There's zillions of ways to go at it. My favorite starts with a find for all the programs that setuid to root. A quick scan with "strings" exposes any foolish use of the "system()" library call. Fix the PATH variable to include your working directory. Override the "IFS" value to "/". Create a trojan replacement for the first element of the path executed by "system()" and make it executable. "usr" or "bin" is commonly the initial pathname. Use the trojan shell script to make a setuid to root copy of /bin/sh. Run the insecure program. Voila! A copy of /bin/sh setuid to root per your script.

[ancient_geezer]

I know, that's why the belly laugh whenever I hear how superior *nix is.

[Golden Eagle]

How about a penguin ping? Or would you rather not.

[TechJunkYard]

Looks like you already did it.

Two of those three don't affect me at all, as they're not even installed. Windows users can't say the same about IE, OE, DCOP, RPC....

[justlurking]

Two of those three don't affect me at all, as they're not even installed.

I updated OpenSSH and sendmail within a few hours, and didn't even have to reboot. Don't need any stinking patches, as I can rebuild and install multiple packages with one command.

One system has Postfix installed instead of sendmail, as I'm considering a switch to that MTA. It's nice to have the choice. If I don't like Postfix, there's at least two more alternatives (Exim and qmail).

[Liberal Classic]

Why wouldn't I not? Software updates is one of the tasks of a responsible administrator.

[PatrioticAmerican]

Linux is solid, perfect, unbreakable, hardened against hackers. I just wonder why Unix has all those patches.

[Coral Snake]

There is KMail too if you are running KDE.

[Coral Snake]

Paging the Penguin Pinger, Calling All Penguins!!!

Satsified.

[Coral Snake]

Sorry Liberal Calssic, That was intended for Golden Eagle.

[Liberal Classic]

I am a ping list of one. :)

[Salo]

If you are pinging the penguin pinger, ping rdb3.

[Coral Snake]

Paging the Penguin Pinger, Calling All Penguins.

Including the two NEW ones.

[justlurking]

There is KMail too if you are running KDE.

No, KMail is a client. I really don't have any use for it, as my Linux system is a server (and the second one is a server testbed). I read my email on a separate (Windows XP) system using Thunderbird or Outlook. I also have a webmail client on the server so that I can read it from any browser.

sendmail, Postfix, etc. are MTA's (message transfer agents). When you actually send email from a client to port 25 (the smtp port), it's an MTA that accepts it, then re-transmits it to the destination (or some intermediate server).

It also accepts email from other systems that is destined for you, depositing in the right place for your email client (or POP3/IMAP server) to find it.

[rdb3]

[amigatec]

I have 2 boxes running OpenSSH both were patched in hours, but neither one was running with the port open. My firewall uses OpenSSH on a different port and is blocked from the outside anyway. I only turn on OpenSSH on my firewall when I need it.
As far as sendmail, I use postfix as a local mail server only.

[Dominic Harr]

Linux is solid, perfect, unbreakable, hardened against hackers.

I've never heard a Linux or Unix person say that.

But I'm constantly hearing Windows folks saying that Linux people say that.

Straw man?

[PatrioticAmerican]

harr, I hear it all the time, here on FR and other places. People constantly say when Windows is hacked that that's the reason they run Linux, because "Linux is secure."