Beware of Windows XP Service Pack 2

Backward compatibility is a good thing. It keeps users happy and ensures

that files they've created in a particular application will still work

with a future generation of that application. I have a PowerPoint

presentation from close to 10 years ago that I haven't opened in, well,

nearly 10 years. But it's good to know that PowerPoint 97, 2000, XP, and

2003 can all open those files.

Windows itself had the old DOS Compatibility Box. It didn't work very

well, and who knows, may have even been designed to get people so riled

up, they'd upgrade, purely out of disgust.

It may be time to get disgusted again.

The Service Pack 2 release for Windows XP is coming. Geared mainly

toward enhancing Windows' meager security capabilities, some of these

fortifications are probably going to cause headaches for older

applications. In other words, they won't work.

This is a big deal and Microsoft knows it. The company has developed an

online training course dealing with SP2. It examines the impact on

existing applications and even includes code samples.

Here's how Microsoft sees it: "With Windows XP Service Pack 2 (SP2),

Microsoft is introducing a set of security technologies that will help

improve Windows XP-based computers' ability to withstand malicious

attacks from viruses and worms." The technologies include network

protection, memory protection, improved e-mail security, and safer


"Together, these security technologies will help make it more difficult

to attack Windows XP, even if the latest patches or updates aren't

applied. These security technologies together are particularly useful

mitigation against worms and viruses. To developers these technologies

will have impacts on the applications that they create and the tools

they use."

Here are just three of the many things you need to know.

The Alerter and Messenger service components of Windows are going to be

disabled by default. Any application or service that uses the Alerter or

Messenger services to communicate with a user will not be successful. In

other words, they won't work.

These services allow simple messages to be communicated between

computers on a network. The Messenger service relays messages from

different applications and services and the Alerter service is intended

specifically for administrative alerts.

Currently, the Messenger service is configured to start automatically

and the Alerter service is set to manual start. In Service Pack 2 for

Windows XP, both of these services are going to be set to Disabled. No

other changes are made to these services. They'll still be there and


So what do you do if you have an app that relies on these services?

According to Microsoft, two avenues of resolution exist. The recommended

technique is to revise the software to use another method to communicate

with the user. This will allow communication with the user to occur in a

more secure way, without having to use the Alerter or Messenger

services. Probably easier said than done. The second way is to have the

application invoke the Alerter or Messenger service before making use of

its services. That would seem to be the easier solution to implement.

Look for changes in the Windows Firewall feature, too.

Previously called Internet Connection Firewall, Windows Firewall is a

stateful filtering firewall for Microsoft Windows XP and Microsoft

Windows Server 2003. Windows Firewall provides protection for PCs

connected to a network by preventing unsolicited inbound connections

through TCP/IP version 4 (IPv4) and TCP/IP version 6 (IPv6).

For some reason known only to Microsoft, this feature has always been

off by default. In Service Pack 2 for Windows XP, the firewall will be

on by default. This applies to both IPv4 and IPv6 traffic, and is

enabled even if there is another firewall already present on the system.

According to Microsoft, had the firewall been on by default, the recent

MSBlaster attack would have been greatly reduced in impact, regardless

of whether users were up-to-date with patches.

After installing Service Pack 2 for Windows XP, the Windows Firewall is

enabled by default. This might break application compatibility if the

application does not work with stateful filtering by default. It may

also conflict with other active software and hardware firewalls. If

that's the case, you'll need to do some reprogramming, or chase whoever

developed that application. If they're out of business, you're out of


And finally, there is the issue of multiple profile support in Windows

Firewall. This feature will allow creation of two firewall policies: one

for when the computer is connected to the corporate network and one for

when it is not. The idea is that you can specify a less-restrictive

policy when the computer is connected to the corporate network and be

more aggressive when that system is being used, say, in a hotel room.

A configuration that is safe on a trusted network may be more

susceptible to attack on the Internet. Therefore, being able to have

ports opened on the trusted network and not on the Internet is critical

to ensuring that only the necessary ports are exposed at any given time.

Multiple profiles for Windows Firewall applies only to computers that

are joined to a domain. Computers that are in a workgroup only have one


According to Microsoft, if an application needs to be listed in the

Windows Firewall exceptions list to work correctly, it might not work on

both networks as the two profiles might not have the same set of

policies. For an application to work on all networks, it must be listed

in both profiles. The fix is simple: If the computer is joined to a

domain, you must ensure that the application is listed in both profiles.

There is a whole lot more than what I've identified here. If you're into

some lengthy reading, visit And the training

course is located at

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