FreeBSD Linux Compatibility Mode Buffer Overflow Vulnerability
BID:1628
Info
FreeBSD Linux Compatibility Mode Buffer Overflow Vulnerability
| Bugtraq ID: | 1628 |
| Class: | Boundary Condition Error |
| CVE: | |
| Remote: | No |
| Local: | Yes |
| Published: | Aug 28 2000 12:00AM |
| Updated: | Aug 28 2000 12:00AM |
| Credit: | This vulnerability was reported in a FreeBSD security advisory dated August 28, 2000. |
| Vulnerable: |
FreeBSD FreeBSD 5.0 FreeBSD FreeBSD 4.1 FreeBSD FreeBSD 4.0 FreeBSD FreeBSD 3.5 FreeBSD FreeBSD 3.4 FreeBSD FreeBSD 3.3 FreeBSD FreeBSD 3.2 FreeBSD FreeBSD 3.1 FreeBSD FreeBSD 3.0 |
| Not Vulnerable: | |
Discussion
FreeBSD Linux Compatibility Mode Buffer Overflow Vulnerability
A vulnerability exists in the Linux compatibility portions of versions 3.x, 4.x and 5.x of FreeBSD. Versions of 5.0 released prior to July 23, 2000, 4.1 prior to July 29, 2000 and 3.5 prior to August 24, 2000, should be considered vulnerable. Releases after these dates are not vulnerable to this problem.
The Linux compatibility module implements what FreeBSD calls a "shadow" filesystem. This is overlayed on the regular filesystem hierarchy. This allows Linux binaries to see files in the shadow filesystem which can mask native files. If a user can create a file in the shadow filesystem which has a long name comprised of machine executable code, it is possible to overwrite values on the stack and execute the content of the buffer containing the filename. This is only the case if the Linux kernel module is loaded, or has been statically compiled in to the kernel. By default, it is not enabled.
A vulnerability exists in the Linux compatibility portions of versions 3.x, 4.x and 5.x of FreeBSD. Versions of 5.0 released prior to July 23, 2000, 4.1 prior to July 29, 2000 and 3.5 prior to August 24, 2000, should be considered vulnerable. Releases after these dates are not vulnerable to this problem.
The Linux compatibility module implements what FreeBSD calls a "shadow" filesystem. This is overlayed on the regular filesystem hierarchy. This allows Linux binaries to see files in the shadow filesystem which can mask native files. If a user can create a file in the shadow filesystem which has a long name comprised of machine executable code, it is possible to overwrite values on the stack and execute the content of the buffer containing the filename. This is only the case if the Linux kernel module is loaded, or has been statically compiled in to the kernel. By default, it is not enabled.
Exploit / POC
FreeBSD Linux Compatibility Mode Buffer Overflow Vulnerability
Currently the SecurityFocus staff are not aware of any exploits for this issue. If you feel we are in error or are aware of more recent information, please mail us at: [email protected].
Currently the SecurityFocus staff are not aware of any exploits for this issue. If you feel we are in error or are aware of more recent information, please mail us at: [email protected].
Solution / Fix
FreeBSD Linux Compatibility Mode Buffer Overflow Vulnerability
Solution:
Patches are available for FreeBSD 5.0-CURRENT, 4.1-STABLE and 3.5-STABLE. Upgrading to a version of these operating systems after the correction date listed in the discussion will also remove this vulnerability.
FreeBSD FreeBSD 3.5
FreeBSD FreeBSD 4.0
FreeBSD FreeBSD 4.1
FreeBSD FreeBSD 5.0
Solution:
Patches are available for FreeBSD 5.0-CURRENT, 4.1-STABLE and 3.5-STABLE. Upgrading to a version of these operating systems after the correction date listed in the discussion will also remove this vulnerability.
FreeBSD FreeBSD 3.5
-
FreeBSD linux.patch
ftp://ftp.freebsd.org/pub/FreeBSD/CERT/patches/SA-00:42/linux.patch
FreeBSD FreeBSD 4.0
-
FreeBSD linux.patch
ftp://ftp.freebsd.org/pub/FreeBSD/CERT/patches/SA-00:42/linux.patch
FreeBSD FreeBSD 4.1
-
FreeBSD linux.patch
ftp://ftp.freebsd.org/pub/FreeBSD/CERT/patches/SA-00:42/linux.patch
FreeBSD FreeBSD 5.0
-
FreeBSD linux.patch
ftp://ftp.freebsd.org/pub/FreeBSD/CERT/patches/SA-00:42/linux.patch
References
FreeBSD Linux Compatibility Mode Buffer Overflow Vulnerability
References:
References:
- FreeBSD Security Information (FreeBSD)