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Security Protection - Harry Waldron (CS)

Security Best Practices, Breaking News, & Updates

April 2005 - Posts

What is DSN Poisoning? - A good overview by Kaspersky

DSN Poisoning - Good Explaination by Kaspersky

We've had a few queries from readers asking what DNS poisoning actually is. As stated yesterday, DNS poisoning is the manipulation of an IP address for a certain DNS entry So what does that really mean? To fully understand this, first you need to know some basics about how addresses work.

There are a few very big DNS servers which provide other, smaller, DNS servers with DNS/I.P. entries. These entries get stored in the cache of the smaller DNS servers. It's not the big servers, but the smaller ones that are being poisoned. Poisoning only lasts until the DNS server rechecks the entries with a large DNS server, so you may also hear this called DNS cache poisoning.

So, if you enter in your browser, the DNS server is queried for the IP address assigned to this DNS name. (DNS names are mainly to make our lives easier). In this case the DNS server will respond with the IP address

So the goal of DNS poisoning is to make the (small) DNS server say that another IP address (one of a site containing malicious content) is assigned to a certain DNS name.

How exactly can servers be poisoned? Well, DNS servers need to run an operating system and software to perform their tasks. Insecure settings and/or vulnerabilities in either of these can lead to the DNS server being poisoned, usually by malformed packets being sent to the server.

How can you protect yourself? This is a tricky question, because as a (DNS) client there is not that much you can do. For example, with modified hosts files, it's a local issue. But in this case the issue isn't local - it's up to your ISP or system administrator to make sure that everything is secure.

When DNS servers are poisoned so that users are directed to clones of legitimate sites, if the poisoning is done correctly, and the cloned sites are carefully constructed, the user won't notice anything unusual.

And I for one don't know many people who know the real IP addresses of the sites they visit.

Internet Storm Center - ISSUES YELLOW ALERT on new security threat

The Internet Storm Center has issued a rare YELLOW ALERT  for a new threat that has recently emerged.  More details will follow from the ISC

DSN Cache Posioning Attacks - Comprehensive Report Available

  The Internet Storm Center has a comprehensive report available which decribes the recent DSN Cache posioning attacks.  This is where an infected server redirects user queries to hostile sites and malware (e.g., viruses, spyware, backdoors) can be loaded automatically if the PC is vulnerable.  

Click here for: DSN Cache Posioning Attack report

Table of Contents:

1. How can others help?
2. How do I recover from a DNS cache poisoning attack?
3. What software is vulnerable?
4. I am a dial-up/DSL/cable modem user -- am I vulnerable?
5. Where can I test my site to see if I am vulnerable?
6. What exactly is DNS cache poisoning?
7. What was the motivation for this type of attack?
8. Weren't DNS cache poisoning attacks squashed around 8 years ago?
9. What was the trigger for the attack?
10. How exactly did this DNS cache poisoning attack work?
11. What domain names were being hijacked?
12. What were the victim sites?
13. What malware was placed on my machine if I visited the evil servers?
14. Got packets?
15. Got snort?

PIE (Persistent Identification Element) - Cookies you can't easily delete

 Using the Macromedia Flash storage areas, a technique has been developed to automatically reload cookies that were deleted within IE.  There are ways to lock MM Flash to prevent the local storage of objects as noted in the links below

PIE (Persistent Identification Element) - Cookies you can't easily delete

The New York company on Thursday unveiled what it calls PIE, or persistent identification element, a technology that's uploaded to a browser and restores deleted cookies. In addition, PIE, which can't be easily removed, can also act as a cookie backup, since it contains the same information.

Two key security settings 

  Macromedia - Flash Player : Local Storage Settings

  Macromedia - Flash Player : Local Storage Pop-Up Question

More links on security settings in Macromedia Flash

 Use the links below to access the relevant settings manager panels directly:

  How do I get to the Settings Manager panel in Macromedia Flash Player?

Windows 2003 SP1 now available

  Microsoft has released Service Pack 1 for Windows 2003 Server and the home page link plus 10 reasons to install are noted below:

Click Here: Windows 2003 Server Service Pack 1

Top 10 Reasons to Install Windows Server 2003 SP1

Reduce your server's attack surface. Reduce your server's attack surface.

Security Configuration Wizard (SCW), one of the new features added to Windows Server 2003 in Service Pack 1 (SP1), uses an intuitive, role-based process to guide administrators through reducing the attack surface. With SCW you can disable unused services easily and quickly, block unnecessary ports, modify registry values, and configure audit settings.

Help protect newly installed servers. Help protect newly installed servers.

In today's security environment there is a continual search for new and potentially exploitable system vulnerabilities. Post-Setup Security Updates (PSSU), another new feature of Windows Server 2003 SP1, blocks all incoming traffic to newly installed servers until the latest patches to Windows Server 2003 are downloaded and applied. PSSU also guides configuration of Automatic Updates when you first log on.

Get firewall protection from startup to shutdown. Get firewall protection from startup to shutdown.

Windows Firewall, the same core firewall technology in Windows XP Service Pack 2, is built into Windows Server 2003 SP1. Windows Firewall in Windows Server 2003 SP1 allows granular control over server and client computers through the use of Group Policy. Moreover, Windows Firewall provides boot-time protection, lowering the risk of attack just after a server is started up and while it is shutting down.

Bolster your defenses with "no execute" hardware support and software. Bolster your defenses with "no execute" hardware support and software.

Data execution prevention (DEP) is a set of hardware and software technologies that performs additional checks on memory to help protect against exploitation of your system by malicious code. Windows Server 2003 SP1 fully utilizes the DEP capabilities built into servers by many manufacturers and further augments those capabilities with DEP software of its own.

Help protect your system services with stronger default settings and reduced privileges. Help protect your system services with stronger default settings and reduced privileges.

Services such as remote procedure call (RPC) and DCOM are integral to Windows Server 2003 and make an attractive target for hackers. By requiring greater authentication for calls of these services, Windows Server 2003 Service Pack 1 helps establish a minimum threshold of security for all applications that use these services, even if they possess little or no inherent security.

Isolate out-of-date virtual private network (VPN) assets. Isolate out-of-date virtual private network (VPN) assets.

VPN Quarantine automatically provides the means for limiting network access for machines on virtual private networks that are not current with regards to security updates. This prevents you from having to write your own ad hoc scripts to affect this facet of sound network security.

Monitor and audit your Internet Information Services (IIS) configuration settings. Monitor and audit your Internet Information Services (IIS) configuration settings.

The metabase is the XML-based, hierarchical store of configuration information for Internet Information Services 6.0. The ability to audit this store allows network administrators to track what, when, who and how a metabase change has been made.

Windows Firewall Policy Management. Windows Firewall Policy Management.

Windows Server 2003 SP1 includes new Group Policies that help IT professionals centralize client and server firewall management, including application rules, port rules, and firewall logging at the client and server to help improve security in the enterprise while maintaining centralized configuration and deployment.

Help secure Internet Explorer. Help secure Internet Explorer.

Internet Explorer now contains many enhancements to help secure Windows Server 2003. For example, Internet Explorer now more effectively stops downloads of spurious files and prevents Web pages from accessing cached objects.

Avoid potentially unsafe e-mail. Avoid potentially unsafe e-mail.

Windows Server 2003 SP1 includes additional refinements to help protect the network. With Outlook Express you can now open mail in plain-text mode, preventing HTML messages from running malicious code. Outlook Express prevents e-mail from downloading external content, stopping a means by which spam senders can validate your e-mail address. Outlook Express also checks e-mail attachments with Attachment Manager, eliminating the need for your own custom code to do so.

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