If it is true ESD, it will have a vey fast rise time ~ 5-10 ns and a) your scope may not have enough bandwidth to see it; b) your scope probe may not have enough BW to pass it through; c) you might damage the scope; d) there is a large peak current during ESD -- could be 10 A -- and this generates a magnetically-coupled pulse which the scope may pick up.
You need good shielding on the probe (and a very short ground lead; likely spiraled around the shaft of the probe to minimize the magnetic coupling) -- but I wouldn't recommend this as if this is ESD, you are at risk of damaging the scope.
If you are trying to prove it's ESD, you can get a high voltage e-field tester to confirm what V is on the cable before connecting it. If you are trying to make the tester more robust, put some diodes to GND/VDD on the leads and then a small R (~ 100 Ω) between that point and the actual IC's input pins. It is well known that the friction from pulling a cable can cause a build-up of charge on it.
Modern testers and ICs are all ESD protected, but not necessarily against the large-ish ESD that could come from a cable (general spec is 1 kV, 100 pF)