I. BACKGROUND
InterSystems Corp.'s Caché is a post-relational database for e-applications that is optimized for web applications. More information about the application is available at
http://www.intersystems.com/cache/index.html.
II. DESCRIPTION
Caché installs with insecure file and directory permissions, thereby allowing local attackers to gain root access by manipulating items in the main package tree. The vulnerability specifically exists because files and directories are open to all users for read, write, and execute operations. An example of such a directory is the ecache/bin directory:
[farmer@vmlinux ecache]$ ls -ld bin
drwxrwxrwx 2 root root 4096 May 2 05:34 bin
The displayed permissions are that of a default install.
III. ANALYSIS
Two attack vectors exist by which any local attacker can gain root privileges:
* Overwriting a globally writeable binary that is executed from a set user id (setuid) root binary by the wrapper, /cachesys/bin/cuxs.
* Executing a server side script from /cachesys/csp/user. The content in that directory is executed as root through the web interface.
IV. DETECTION
Caché Database 5.x is affected. Older versions may be vulnerable as well.
V. WORKAROUND
Administrators can prevent exploitation by making file permissions more restrictive. This should prevent attackers from overwriting binaries or placing scripts in /cachesys/csp/user.
VI. VENDOR FIX
InterSystems provided an alert to its customer base that is viewable at http://www.intersystems.com/support/flash/index.html. In it, the company said that the installation defaults will be changed in Caché 4.1.16 and 5.0.3.
VII. CVE INFORMATION
The Mitre Corp.'s Common Vulnerabilities and Exposures (CVE) Project has assigned the identification numbers to these issues:
CAN-2003-0497 overwrite Caché using setud cuxs program
CAN-2003-0498 code injection into /cachesys/csp
VIII. DISCLOSURE TIMELINE
11 MAR 2003 First attack vector disclosed to iDEFENSE
18 APR 2003 Second attack vector disclosed to iDEFENSE
10 JUN 2003 Research Completed on Issues
10 JUN 2003 InterSystems Corporation notified
11 JUN 2003 Response from David Shambroom of InterSystems
01 JUL 2003 Coordinated public disclosure
IX. CREDIT
Larry W. Cashdollar (lwc@vapid.ath.cx) discovered this vulnerability.
