In the recent federal probe of retail data breaches, most of the merchants had been unaware of the breaches until informed by government or banking officials. The reason for this is the lack of tools and/or poor procedures for logging network and database access and the general lack of review of this information on a regular basis. In short, there is a good chance that if your company is being breached now, you won't find out about it until the stolen data is used to commit fraud.
People always blame the lack of up-to-date wireless encryption for the TJX security breach. News stores feature reporters "wardriving" mall parking lots trying to find unencrypted access points, which is very "exciting" but only part of the story. The less exciting part is that even if the merchants in question were using weak wireless encryption, the breaches could have been stopped dead if the retailers had adequate access control logging and alerting capabilities. In addition to stopping external cracks, logging and alerting is even more important to catch "rogue" insiders, particularly those who have privileged access to systems.
Indeed, in this federal probe, the security systems of only one retailer even detected the intrusion. And the feds want that retailer's identity to be kept secret.
In surveys, retail wireless security is not seen as a big problem. Keeping up with the latest encryption protocols is regarded as not that big a deal. (The TJX breach, when it was first reported, was a huge wake-up call.) Rather, the "big" problem is that most retailers do not have sufficient tools to help them sort through the network access control logs, the file integrity monitoring logs, the intrusion prevention logs, etc. Some of the retailers admit that they don't always keep the logging turned on. Security professionals use the technical term "oops" to refer to this situation.
Assuming that you're a retailer who has logging turned on, one of the most common problems with logging, monitoring and alerting software is that it has to be "tuned." If you don't set it up properly, or monitor the proper files, you can easily wind up having to store (and manage) a few terabytes of log data. Unless you happen to be in the data storage business, this can quickly become a pain. Some retailers assign a person to review this data. Usually it's a person they don't like too much, as "tedious" doesn't begin to describe the nature of the manual log review task. Using analytical software or a service is a superior option.
It's fair to say that only about 10-15 percent of merchants are happy with both the accuracy and the level of alerting detail they get from their tool and/or their service provider. Part of this dissatisfaction is because of the whole "tuning" problem, which means that both the accuracy and the level of detail improve over time. The other reason why merchants are unhappy about logging and alerting is that in highly decentralized environments, all of the data is being aggregated and/or reviewed by third parties. This process itself has inherent risks that are troubling to security managers. Clearly, there's no easy answer.
There are some tools and services which retailers are willing to recommend to their peers. If you'd like to know the names of these companies, just visit the PCI Knowledge Base, and search on the term "logging." I recommend this because it seems wrong to just "namedrop" some vendors without providing the context that you'd get from reading the comments from the retailers in their original form.