If you really think any anti-virus out there is able to defend you against targeted attacks from government intelligence services, then I've got some news for you. IMHO those vendors who say they detect it are less truthful then those who say nothing at all, because they severely overestimate the capabilities of their product. On top of that a grand conspiracy of purposefully crafted backdoors in your software isn't necessary either.
If anything, an anti-virus makes you an easier target for a targeted attack. That goes especially for products with a web-anti-virus module that processes remote code with admin privileges or products that inject privileged content into sandboxed processes. Then you can achieve complete sandbox bypasses and instant admin privileges without even having to tamper with the sandbox or privilege escalation techniques.
So please install an anti-virus to protect you from the NSA, lol.
Well to some degree you are right, But you have to understand that AV vendors actually do detect governmental sponsored malware and attacks. However some of them are forced by law to white list them as they are not targeted at the civilian population.
You do underestimate the potential that AV programs have, specially the industrial versions which are modular build and come with a basic set out of the box. Symantec EP and Sophos EP are great examples of that.
Ones you start adding rules and protocols yourself their products truly become magic.
Same goes for custom hardware firewall gateway builds, they are entirely custom and have very strict and specific rules.
And if managed properly they take months and months to break down from a attack POV. And yes they do detect everything you trow at them for the plain and simple reason they have been configured in such way that it detect ANYTHING as bad if not pre-whitelisted.
In regards to your comment about crafted backdoors in software, it seems you are either blind or sleeping as windows 95 up to windows 8 have been modified for law enforcement access by using backdoors and other tricks.
The new motherboards do even have a hardware chip that serves as a entree point and you cannot block it, stop it or detect it.
Any OS and any internet, gps, radio/tv or communication device in general has build in access points... that's nothing new.
However the juicy part is that the access methods to those devices have been either given, bought or demanded by law/court or in some cases been hacked so that a agency like NSA can tap in.
Or do you really think the NSA and its crew are that brilliant? They literally forced companies to lower their security otherwise the NSA could not tap in.
Encryption is a good example, there are protocols that are near un-hackable even while using a super pc. But by law they are forbidden to be used in american based software as it would stop NSA death in their tracks.
Germany is stopping their windows contracts and move to a custom build Linux hybrid with domestic developed security why you think that is?
The NSA can do anything they like without much trouble because their foreign policy has shaped the landscape as such.
Things however start to change as NON US companies start to develop technology that is far past NSA capabilties...
Just saying.