The length of time between the development of security patches and the development of exploits targeting the security holes they address has been dropping for some time.

Hackers exploit this period of time - the so-called patch window - to launch attacks against unpatched machines. Typically, exploits are developed by skilled hackers versed in the arcane intricacies of reverse engineering.

However, hackers have now begun using off-the-shelf tools to at least partially automate this process, a development that might lead to exploits coming out hours instead of days after the publication of patches.

Security researchers at Berkeley, the University of Pittsburgh, and Carnegie Mellon have launched a research project investigating the approach (pdf.), which relies on comparing the configuration of patched and unpatched machines.

In some cases hackers are able to develop an exploit just minutes after receiving a patch. Fortunately, for now, the technique is rather hit and miss. More often than not the semi-automated process creates tools that only crash vulnerable applications, rather than creating a means to inject hostile code onto vulnerable machines.

Over time the technique is only likely to get more reliable.

The researchers suggest that secure distribution of patches might mitigate against the approach by keeping patches out of the hands of hackers. But, as security watchers at the Internet Storm Centre (ISC) point out, such an approach would take away the benefits of automated patching.

The application of temporary workarounds may be useful in setting up defences against the evolution of automated exploit generation, ISC handler John Bambenek writes. ®

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