SNAP Innovation's PrimeBase Database 4.2 poor default file permissions and use of symlinks during install.
September 1, 2003

I. BACKGROUND

From the readme.txt file

"The PrimeBase Database Server is a relational Database Management System (DBMS) for Mac, UNIX and Windows platforms. The PrimeBase Database Server supports all common database access standards (PBT, SQL, ODBC, JDBC, PHP, Perl, RealBasic, EOF and DAL) and protocols (TCP/IP, Shared Memory and Appletalk)."

II. DESCRIPTION

Poor use of temporary files during installation.

I noticed the PrimeBase install script creates the following files in /tmp:

[nobody $] ln -s /etc/shadow /tmp/PrimeBase.log

Then if a malicious user has previous knowledge of the administrators installation of PrimeBase the contents of /etc/shadow will be overwritten with the contents of PrimeBase.log.

LOG="/tmp/PrimeBase.log"

echo "$str:[y/n]" | tee $LOG
echo "PrimeBase Installation: $now" >> $LOG

2. Poor default file permissions.
A malicious local user could manipulate the binaries for PrimeBase used by the administrator and execute arbitrary code. The attacker would need to wait until the Database was restarted or the system rebooted.

root@Fester local]# ls -ld /usr/local/primebase drwxrwxrwx 6 root root 4096 Sep 1 13:57 primebase

III. ANALYSIS

Local attackers can exploit these vulnerabilities to clobber root owned system files and modify software binaries. This could possibly lead to a denial of service or system compromise.

IV. DETECTION

PrimeBase Data Server Build 4212.
http://www.primebase.com/en/index.html

V. WORKAROUND

temp file vulnerability.

Boot the system into single user mode only and ensure no other users are logged in during installation.

2. Default file permissions.
Change directories to more restrictive ownerships (untested).

VI. VENDOR FIX

Vendor will fix issues in next release.

VII. CVE INFORMATION

The Mitre Corp.'s Common Vulnerabilities and Exposures (CVE) Project has not assigned an identification number to this issue.

VIII. DISCLOSURE TIMELINE

9/16/2003       Issue disclosed to Vendor.
9/26/2003       Response from Vendor.

IX. CREDIT

Larry W. Cashdollar (http://vapid.dhs.org) discovered this vulnerability.