With a house on fire you're taking reasonable action to protect life.
In general, when you do something you then take responsibility for the consequences of that action. Thus, if there was a tiny fire and you flooded the house with water and foam and caused considerable water damage you may find the home owner suing for damage caused. You could counter by saying you prevented much more damage, but they'd say that a competent fire-fighter would have done that and avoided all the water damage.
The analogy fails (as they always do) because there are specific criminal laws around computer misuse / unauthorised use. Running software on someone's machine without their permission is unlawful.
You may have mitigation if you can claim that the harm from the botnet was more severe than the harm caused by the clean-up-hacking.
It is frustrating. I used to say "Don't fight abuse with abuse", but it's pretty hard to keep that attitude in the face of so much malware and spam.
In general, when you do something you then take responsibility for the consequences of that action. Thus, if there was a tiny fire and you flooded the house with water and foam and caused considerable water damage you may find the home owner suing for damage caused. You could counter by saying you prevented much more damage, but they'd say that a competent fire-fighter would have done that and avoided all the water damage.
The analogy fails (as they always do) because there are specific criminal laws around computer misuse / unauthorised use. Running software on someone's machine without their permission is unlawful.
You may have mitigation if you can claim that the harm from the botnet was more severe than the harm caused by the clean-up-hacking.
It is frustrating. I used to say "Don't fight abuse with abuse", but it's pretty hard to keep that attitude in the face of so much malware and spam.