In reality, all mods for every game available on the internet could potentially be something malicious.
The same goes for modpacks on Technic launcher, Atlauncher, FTB/Twitch/Curse and Voidswrath launchers.
Our official modpacks are safe, as is our launcher. When it comes to the thousands of packs on the Platform... it's really hard to say.
We haven't got any reports of anything that could've harmed anyone, and I've been here long enough to remember if there was any.
If anything would come up and people report it, we will take action on it.
considering the minecraft.jar distribution itself is illegal and anyone doing so will get in trouble with Mojang. Such packs should and will be removed. Most of those happen to be young kids who doesn't know how to make modpacks
the only jar that needs to come with a custom pack is modpack.jar which is only Forge renamed
Edit. this doesn't belong in Tekkit pack discussion.
Moved to Cafe Lame