Drack found crumbs, and while there’s a chance that the lazy old Krogan is just trying to get out of a chore, there could also be some poor scavenging critter likely to become his next meal if you don’t intervene. Or perhaps some space pest that’ll dangerous diminish you store of goods? Either way - Ryder the exterminator must see to this matter of cosmic importance!
You can start from the Galley and scan some crumbs on the counter, then follow it down to the Cargo Bay - specifically near the door to the Storage room. or you can just head to the aforementioned location and scan the crumbs near some crates on the ground north of the door to the Storage room. After scanning these crumbs, Ryder will decide that crafting a "humane trap". Why humane? Well, because if left alone, Drack would probably eat the varmint anyways, so building a lethal trap would be somewhat redundant. Plus, it wouldn’t allow you to make a choice concerning said pest later on.
Head to the Research and Development terminal and select the "Special Items" tab, where you’ll now find a "Humane Trap" ready for construction. It’ll set you back three whole Aluminum, which shouldn’t be able trouble to afford. Craft it, then return to the crumbs outside of the Storage room and plant the trap. To finish this quest you’ll have to hop off the Tempest (perhaps to visit Kadara Port and obtain some popcorn for Vetra?). When you return, you’ll have captured Drack’s tormentor.
Return to the trap near the Storage room and Suvi will inform you of your success. Examine the trap to confront the cute little rodent inside, whose fate is now in your hands - either release it off-world, or keep it as a pet. Who doesn’t want a cute little "hamster" as a pet? Or is it possibly a… miniature giant space hamster? Hmm… Only long term analysis from within the comfy confines of a cage will tell! For completing this mundane quest you’ll earn 29 AVP.