| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Wed, 06 Dec 2017 08:32:48 +0000 From: "Mark Wadham" <fd@....io> To: fulldisclosure@...lists.org Subject: [FD] macOS High Sierra 10.13.1 insecure cron system Recently I was working on an security issue in some other software that has yet to be disclosed which created a rather interesting condition. As a non-root user I was able to write to any file on the system that was not SIP-protected but the resulting file would not be root-owned, even if it previously was. This presented an interesting challenge for privilege escalation - how would you exploit this to obtain root access? The obvious first attempt was the sudoers file but sudo is smart enough not to process it if the file isn't root-owned so that didn't work. I then discovered (after a tip from a friend - thanks pndc!) that the cron system in macOS does not care who the crontab files are owned by. Getting root was a simple case of creating a crontab file at: /var/at/tabs/root with a 60-second cron line, eg: * * * * * chown root:wheel /tmp/payload && chmod 4755 /tmp/payload and then waiting for it to execute. It's not clear if this is a macOS-specific issue or a hangover from the BSD-inherited cron system, I suspect the latter. The issue has been reported to Apple so hopefully they will fix it. Ref: https://m4.rkw.io/blog/macos-high-sierra-10131-insecure-cron-system.html _______________________________________________ Sent through the Full Disclosure mailing list https://nmap.org/mailman/listinfo/fulldisclosure Web Archives & RSS: http://seclists.org/fulldisclosure/
Powered by blists - more mailing lists