That's the logical conclusion to draw from a new report from Verizon's security services group (download PDF). It's a follow-up to Verizon's big report in June that sifted through data from more than 500 cases the company was hired to investigate over four years.

This time, Verizon sliced and diced the data for the four biggest industry groups: financial services, technology services, retailers and restaurant chains. That alone makes it useful to IT security people.

For example, in financial and tech services, almost 40 percent of breaches came from the inside, much more than in other groups. Retailers and restaurant chains took months to discover a breach, compared with weeks for tech firms and days for financial companies. And attack techniques varied with each industry: Deceit was big for financial firms, while hacking was huge for retailers and restaurants.

But a few things they all shared: By far, the favorite loot was credit and debit card data. And it was usually a third party, not someone inside the breached company, that discovered the break-in.

All this is worrisome enough. But when I talked to Bryan Sartin, who directs Verizon's investigative response operation and co-authored the new report, he told me something more troubling.

It turns out that attacks—especially those by organized gangs—come in waves. For example, starting around 2001, attackers focused on security holes in retailers' and restaurants' payment gateways. Often, they would target a specific company, then try different attacks until one worked—everything from network hacks to Wi-Fi war driving and even physical trespassing.

Then, in 2003, the style shifted. There were lots of network-based automated attacks—scanning and SQL injections—often from compromised servers overseas.

Today, Sartin told me, there's a new pattern: Crooks are targeting companies that use the same software— say, a particular point-of-sale system. They find a security hole, then track down other businesses that use the same POS system. (That's often as easy as checking the vendor's website for reference customers.)

Then crooks can compromise lots of targets in the same industry at once, using exactly the same attack.

See where this leads? If you're using the same software as a competitor who's been hit, chances are good that you're a target too. If an attack worked against him, it probably will work against you.

And if it happens to a competitor of one of your trusted partners, you're in the same situation.

And because it can take months for a breach to be found (usually by an outsider, remember), it's likely that by the time you've heard about that breach, you've already been attacked.

Of course, you probably don't know exactly what software your competitors use. So if you hear about any attack on a competitor, don't waste time gloating. Hit your own logs fast, looking for any unusual activity that could indicate a breach.

And if you haven't heard about a breach among your competition yet, don't relax—especially if you're in a credit-card-heavy business like retail. Keep scanning logs and watching for signs of a breach. Remember, you are a target.

Don't be the last to find out you're a victim.