From info@calderasystems.com Fri Apr 30 15:51:58 1999 From: Caldera Systems Information To: caldera-announce@rim.caldera.com Date: Fri, 30 Apr 1999 11:29:51 -0600 Reply-To: info@caldera.com Subject: SECURITY [CSSA-1999:010.0] -- rsync may change directory permissions inadvertently -----BEGIN PGP SIGNED MESSAGE----- ______________________________________________________________________________ Caldera Systems, Inc. Security Advisory Subject: rsync may change directory permissions inadvertently Advisory number: CSSA-1999:010.0 Issue date: 1999 Apr 30 Cross reference: ______________________________________________________________________________ 1. Problem Description There's a security problem with rsync which can cause the permissions of an users home directory to be changed. The bug is fairly obscure, but it's fixed in ver 2.3.1 The problem happens if all of these conditions hold true: 1) the source file list contains exactly one filename and that is the name of an empty directory 2) the source directory name is specified on the command line as "somedir/" or "somedir/." or "." not as "somedir" 3) the destination directory doesn't exist 4) you have recursion and permission transfer enabled (the -a option will do this) 5) the working directory of the receiving process is not the destination directory (this happens when you do remote rsync transfers) (the short summary is that you need to be transferring an empty directory into a non-existent directory) In that case (which is quite rare) the permissions from the empty directory in the source file list were set on the working directory of the receiving process. In the case of a remote rsync over rsh or ssh this means that the permissions on your home directory are changed to those of the empty directory you are transferring. This is a serious bug (and security hole) as it may change your home directory permissions to allow other users access to your files. A user can't exploit this hole deliberately to gain privileges (ie. this is not an "active" security hole) but a system administrator could easily be caught by the bug and inadvertently compromise the security of their system. To see if you have been hit by this bug you should look at the permissions on your home directory. If they are not what you expect then perhaps you have been bitten by this bug. The fix is to chmod your home directory back to the correct permissions and upgrade to rsync 2.3.1. The bug is in the receiving side of rsync, so it is quite safe to continue to use older anonymous rsync servers as long as you upgrade your client. This bug has been present in all versions of rsync. 2. Vulnerable Versions Systems: OpenLinux 1.0, 1.1, 1.2, 1.3, 2.2. Packages: previous to rsync-2.3.1 3. Solutions The proper solution is to upgrade to the rsync-2.3.1-1.i386.rpm 4. Location of Fixed Packages The upgrade packages can be found on Caldera's FTP site at: ftp://ftp.calderasystems.com/pub/OpenLinux/updates/2.2/current/RPMS/ The corresponding source code package can be found at: ftp://ftp.calderaystems.com/pub/OpenLinux/updates/2.2/current/SRPMS 5. Installing Fixed Packages Upgrade the affected packages with the following commands: rpm -q rsync && rpm -U rsync-2.3.1-1.i386.rpm 6. Verification The MD5 checksums (from the "md5sum" command) for these packages are: 76a89fabb96e61adb1df5c14d955c08b RPMS/rsync-2.3.1-1.i386.rpm c16447d52d0166ab94666f2a4c1b9984 SRPMS/rsync-2.3.1-1.src.rpm 7. References This and other Caldera security resources are located at: http://www.calderasystems.com/news/security/index.html Additional documentation on this problem can be found in: This security fix closes Caldera's internal Problem Report 4509. 8. Disclaimer Caldera Systems, Inc. is not responsible for the misuse of any of the information we provide on this website and/or through our security advisories. Our advisories are a service to our customers intended to promote secure installation and use of Caldera OpenLinux. ______________________________________________________________________________ -----BEGIN PGP SIGNATURE----- Version: 2.6.3i Charset: noconv iQCVAwUBNylzeen+9R4958LpAQF2hwQAq3E7kEh2LRDFnDa/E9FuK+0ArNqUEgr8 rJ5EU8sgwaA9IGNRja19op1Ak/SCK4GYohPvYpoR6tSa0P+C7McrCpO0S0fS2bQg XiXyrbndb5erlnPjxJLFeozXtn1vIZ2jFI7Y4TvI/kQlsWbxqUAoM6tH1diHia6Z mbQFM4fHD5Q= =brbM -----END PGP SIGNATURE----- - Notes: To learn how to use this list server, email a "help" command to majordomo@rim.caldera.com.