PostgreSQL security releases 8.1.4, 8.0.8, 7.4.13, 7.3.15

PostgreSQL versions 8.1.4, 8.0.8, 7.4.13 and 7.3.15 have been released
fixing two security issues.

Details of vulnerability 1

Vulnerability type: SQL Injection
Remotely exploitable: Depends on client

Affected versions: PostgreSQL 8.1.0-8.1.3, 8.0.0-8.0.7,
7.4.0-7.4.12, 7.3.0-7.3.14
Fixed versions: PostgreSQL 8.1.4, 8.0.8, 7.4.13, 7.3.15

Affected platforms: All

CVE: CVE-2006-2313
(http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-2313)

Vulnerability description

An attacker able to submit crafted strings to an application that will
embed those strings in SQL commands can use invalidly-encoded multibyte
characters to bypass standard string-escaping methods, resulting in
possible injection of hostile SQL commands into the database. The
attacks covered here work in any multibyte encoding.

Details of vulnerability 2

Vulnerability type: SQL Injection
Remotely exploitable: Depends on client

Affected versions: PostgreSQL 8.1.0-8.1.3, 8.0.0-8.0.7,
7.4.0-7.4.12, 7.3.0-7.3.14
Fixed versions: PostgreSQL 8.1.4, 8.0.8, 7.4.13, 7.3.15

Affected platforms: All

CVE: CVE-2006-2314
(http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-2314)

Vulnerability description

The widely-used practice of escaping ASCII single quote "'" by turning
it into "\'" is unsafe when operating in multibyte encodings that allow
0x5c (ASCII code for backslash) as the trailing byte of a multibyte
character; this includes at least SJIS, BIG5, GBK, GB18030, and UHC. An
application that uses this conversion while embedding untrusted strings
in SQL commands is vulnerable to SQL-injection attacks if it
communicates with the server in one of these encodings. While the
standard client libraries used with PostgreSQL have escaped "'" in the
safe, SQL-standard way of "''" for some time, the older practice remains
common. As of PostgreSQL versions 8.1.4, 8.0.8, 7.4.13 and 7.3.15, the
server has been modified to reject "\'" when the client is using one of
these encodings.
This does NOT in itself fix all variants of the problem, but it will
make it obvious that such a client is broken and in need of repair.

More information is available on the PostgreSQL website at
http://www.postgresql.org/docs/techdocs.52.

Solution

Upgrade to version 8.1.4, 8.0.8, 7.4.13 or 7.3.15 respectively,
available from http://www.postgresql.org/ftp/ in both source and binary
formats.

Mitigating factors

• If client_encoding is a single-byte encoding (e.g., one of the
  LATINx family), there is no vulnerability.

• If both client and server encoding is UTF8, there is no vulnerability.

• If application always sends untrusted strings as out-of-line
  parameters, instead of embedding them into SQL commands, it is not
  vulnerable. This is only available in PostgreSQL 7.4 or later.

• If application cannot pass invalidly encoded data to the server,
  there is no vulnerability (this probably includes all Java and .Net
  applications, for example, because of the platforms handling of
  Unicode strings).

Workarounds

• Changing to a non-multibyte client_encoding will protect against
  both vulnerabilities.

• Changing to UTF8 encoding and upgrading to a fixed version of
  PostgreSQL will protect the system without client side changes.

Credits

The PostgreSQL Global Development Group thanks Akio Ishida and Yasuo
Ohgaki for reporting these vulnerabilities.