I just read about the new vulnerability in Webmin and after taking a look at the module involved, I was surprised at how easy it would be to make this mistake. The problem is that Webmin passes user input to the Sys::Syslog module without escaping it. The issue with this is that the Syslog module uses printf to format its output and someone can easily put something like %n in the string which will cause the script to abort because of a write error.

Knowing this now, I'll be sure to look over all my scripts that use Sys::Syslog and will be sure to pay careful attention in the future to modules that say anything about using printf. However, I was wondering if there was any general rule that I am missing here. It just seems to easy to unknowingly pass something to a module that you don't know uses printf. Is there any way taint mode can check for this? Thanks!

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