Which WarMachine armor? Just the standard armor can take Venom out
http://marvel.wikia.com/War_Machine_Arm ... XL-1000%29 Various munitions are available: depleted uranium, high explosive, concussion, thermite, tear gas, tracer, flare, smoke, anti-tank, anti-ship, flame, fire suppressant, radio repeater or sub-nuke.
so he has fire covered, and concievably has several ways to make sonic damage (most concussion damage has a loud enough boom)
and as for a fight in the middle of no where, well.. WM can hover high above, out of Venoms reach. nothin he can really do about that.
the Eidolon Warwear, a more recent armor, uses "plasma-based" weaponry presumably comparable to fire.
and then the "
Rhodey transformed the satellite into its armor mode and effectively destroyed a Skrull armada that had been approaching the Earth" armor...
Now, i'm not saying venom is a slouch or anything, but WM has over 9000 advantages on this one