Win 7 64bit - Geforce GTX 670
Broken: 2.78 4bb1e22 and 2.79 7b397cd
When applying a texture to a cube in cycles, using generated co-ordinates and a box projection for the image mapping, 3 of the 6 faces have their textures applied back to front (also occurs with object co-ordinates and flat mapping). This behaviour is consistent in the viewport (material and rendered modes) and also in the render result. Adding a cube with generate UV's ticked does not correct this problem.
In the example file and attached image, the cube on the left indicates this behaviour. The cube on the right uses a custom UV map and flat projection for image mapping to achieve what I would consider the most appropriate result, for texturing a simple cubic object.
Exact steps for others to reproduce the error
Create material node setup using image texture:
File example -