Netscape Communicator /tmp Symlink Vulnerability
BID:1201
Info
Netscape Communicator /tmp Symlink Vulnerability
| Bugtraq ID: | 1201 |
| Class: | Race Condition Error |
| CVE: | |
| Remote: | No |
| Local: | Yes |
| Published: | May 10 2000 12:00AM |
| Updated: | May 10 2000 12:00AM |
| Credit: | This vulnerability was posted to the Bugtraq mailing list on May 10, 2000 by foo <[email protected]> |
| Vulnerable: |
Netscape Communicator 4.73 Netscape Communicator 4.72 Netscape Communicator 4.61 Netscape Communicator 4.51 Netscape Communicator 4.7 Netscape Communicator 4.6 Netscape Communicator 4.5 |
| Not Vulnerable: | |
Discussion
Netscape Communicator /tmp Symlink Vulnerability
Netscape Communicator version 4.73 and prior may be susceptible to a /tmp file race condition when importing certificates. Netscape creates a /tmp file which is world readable and writable in /tmp, without calling stat() or fstat() on the file. As such, it is possible, should a user be able to predict the file name, to cause a symbolic link to be created, and followed elsewhere on the file system.
Additionally, as the file is created mode 666 prior to being fchmod()'d to 600, there may be a window of opportunity for altering the contents of this file.
This issue has only been demonstrated on the Linux binary, for glibc. The sparc Solaris binary does not behave this way.
Netscape Communicator version 4.73 and prior may be susceptible to a /tmp file race condition when importing certificates. Netscape creates a /tmp file which is world readable and writable in /tmp, without calling stat() or fstat() on the file. As such, it is possible, should a user be able to predict the file name, to cause a symbolic link to be created, and followed elsewhere on the file system.
Additionally, as the file is created mode 666 prior to being fchmod()'d to 600, there may be a window of opportunity for altering the contents of this file.
This issue has only been demonstrated on the Linux binary, for glibc. The sparc Solaris binary does not behave this way.
Exploit / POC
Netscape Communicator /tmp Symlink Vulnerability
Predict the name of the temporary file.
ln -sf /elsewhere /tmp/<tmpfilename>
Alternately, a program which watches for the creation of these temporary files, opens them upon their creation, and alters the contents can be written.
Predict the name of the temporary file.
ln -sf /elsewhere /tmp/<tmpfilename>
Alternately, a program which watches for the creation of these temporary files, opens them upon their creation, and alters the contents can be written.
Solution / Fix
Netscape Communicator /tmp Symlink Vulnerability
Solution:
Currently the SecurityFocus staff are not aware of any vendor supplied patches for this issue. If you feel we are in error or are aware of more recent information, please mail us at: [email protected].
Solution:
Currently the SecurityFocus staff are not aware of any vendor supplied patches for this issue. If you feel we are in error or are aware of more recent information, please mail us at: [email protected].
References
Netscape Communicator /tmp Symlink Vulnerability
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