Some vulnerabilities have been reported in Ruby, which can be exploited by malicious people to bypass certain security restrictions, cause a DoS (Denial of Service), and conduct spoofing attacks.

1) Multiple errors in the implementation of safe level restrictions can be exploited to call "untrace_var()", perform syslog operations, and modify "$PROGRAM_NAME" at safe level 4, or call insecure methods at safe levels 1 through 3.

2) An error exists in the usage of regular expressions in "WEBrick::HTTPUtils.split_header_value()". This can be exploited to consume large amounts of CPU via a specially crafted HTTP request.

3) An error in "DL" can be exploited to bypass security restrictions and call potentially dangerous functions.

4) The vulnerability is caused due to resolv.rb not sufficiently randomising the DNS query port number, which can be exploited to poison the DNS cache.

The vulnerabilities are reported in the following versions:
* 1.8.5 and prior
* 1.8.6-p286 and prior
* 1.8.7-p71 and prior

Solution
Update to a fixed version.
Further details available to Secunia VIM customers

Provided and/or discovered by
The vendor credits:
1) Keita Yamaguchi
2) Christian Neukirchen
3) sheepman
4) Tanaka Akira

Changelog
Further details available to Secunia VIM customers

Original Advisory
http://www.ruby-lang.org/en/news/2008/08/08/multiple-vulnerabilities-in-ruby/

Deep Links
Links available to Secunia VIM customers