Are droids hackable in the Star Wars universe?

Question

Are droids hackable in the Star Wars universe?

For example, theoretically,

• could an Imperial hacker hack into C3P0's memory (let's say while the poor robot is in pieces in the Cloud City, before Chewie finds and rebuilds "him")? Could said hacker read and possibly alter C3P0's memories? Could he install "subliminal suggestions", in other words, viruses?
• could the Rebels hack, in the very beginning of "The Empire Strikes Back", into the Imperial Probe's AI remotely (via a WiFi or similar channel) and alter either or both the droid's perception (so that it sees only the snow fields, not the Rebel Base) and the signals it sends out, back to the Imperial recon divisions?
• could Imperial hackers aboard the Death Star hack into the attacking X-Wings' astromech droids (R2s) and cause the starfighters to crash into the walls or at least malfunction?

I know the idea itself feels somewhat strange to the world -- even though R2D2 does hack into the systems of the Death Star in "A New Hope", finding out where Leia is held captive and stopping the walls of the trash compactor before it would kill the "party" --, yet this day and age brings up such "technological updates" questions unavoidably as quite a number of the fans of the SW universe think about computers and systems with an up-to-date mindset.

Note: Should you feel interested, I have asked practically the same Q on rpg.SE with roleplaying games in focus.

Answer 1

Nowhere is there any indication of R2D2 and C3P0 having any capability of wireless (rather than through cables with connectors wired to them) access to their systems.
And when R2D2 hacks into the Death Star's systems, he does the same, he uses a connector he extends from his body to connect himself to the station's computer.

I'd not think it unreasonable to assume that, had the droids fallen into the hands of the imperial intelligence services or military, they'd have no trouble digging into their information stores and extracting whatever they wanted. As at least R2D2 was a modified version of a standard drone model (C3P0 if I recall correctly was constructed as a hobby project out of scrap parts, but I don't know if those parts were all from the same model drone) information on how to do this would likely be on file.
Of course the custom modifications could have included extra security features turning it into a challenge, or self-destruct capabilities to prevent data being compromised, but nothing of this is mentioned anywhere in the movies.

Also, when the droids are captured by the jawas, they are fitted with restraining bolts which are clearly crude devices intended to hack into their systems, rendering their autonomous functions partially incapacitated. No doubt the industrial might of the Empire can come up with something a lot more advanced than a group of jawas on a remote desert planet.

Answer 2

Yes.

• R2D2 was hacked remotely by a Force user (Irek Ismaren) as depicted in Children of the Jedi - who was able to interact with technology by the means of Subelectronic converter, to make R2D2 try and kill Solo family.

• Verpine hackers (slicers) hack into all sorts of things in EU books

Answer 3

Droid are absolutely hackable in the Star Wars Universe, especially by other droids. It's a difficult process, and not possible to do remotely (without very specialized hardware on both ends), but it can be done.

The seventh book of the X-Wing Series, Solo Command features this as a major plot point.

Lara Nostil (in reality, the former Imperial slicer/spy/infiltrator Gara Petothel) after having been discovered and fleeing the Wraiths

finds herself aboard the Iron Fist, in a position of limited trust and under moderate surveillance. She brings her X-Wing with her, as well as

Tonin, her R2 unit

though his memory has been wiped. This, however, proves to be a facade, as

Lara actually set him up with a memory backup

Working together, they attempt to take down the Iron Fist. The single most significant portion of this is not

Lara/Gara hacking the ships systems

but rather

Tonin ordering his legions of subverted and specialized Mouse Droids to start tearing apart the ship's systems, including communications and hyper drive.

The book actually has at least one significant portion of a chapter devoted to

Tonin enticing, capturing, and hacking the other droids.

The reprogramming is quite successful, and it works extremely well.

Since we have thus seen that droids can be accessed (and we also see the droids being used as spies, playing back their visual records for her) it stands to reason that 3P0 could have been sliced at Cloud City, had the Imperials cared enough to do so (they didn't, and may not have had the technical specialists it would have required on hand). It cannot, however, be done wirelessly, so your other scenarios would not have been practical.

Answer 4

In the Disney Canon, you have Star Wars Rebels episode "Double Agent Droid" (S3E18) in which an Imperial Information Officer remotely hacks and takes control of Chopper while Chopper is trying to steal Imperials access codes from an ISB base.

Answer 5

Back when Decipher had the license to produce a SW CCG, they made the following cards:

4-LOM: "Overrode and reprogrammed its own self-governing software" (hacked itself!) to become a bounty hunter.

and

U-3PO: "This protocol droid served in the House of Alderaan's Diplomatic Corps. Imperials altered its programming for espionage, making the droid an unwitting spy for the Empire."

and

Program Trap: "Imperial slicers imbed [sic] a secret command in a droid's primary performance banks. A predetermined trigger causes a power overload, destroying the droid and anything nearby."

Answer 6

Yes, in Canon also

In the Clone Wars series, we see a B2 droid which is hacked by the Republic engineers to assist in a covert operation.