iDEFENSE Security Advisory 07.01.03: Caché Insecure Installation File and Directory Permissions

["iDEFENSE Labs" <labs () idefense com>]

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iDEFENSE Security Advisory 07.01.03:
http://www.idefense.com/advisory/07.01.03.txt
Caché Insecure Installation File and Directory Permissions
July 1, 2003

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 notifed
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.


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