Brick and mortar buildings like this, this, and this are a common sight in post-Soviet cities. They are colloquially called transformer booths because they house transformer (sub)stations. They are not all ugly but it’s understandable that some people would rather see them painted in bright colors, especially in winter.
Like this one (here’s an earlier version of its graffiti). The four sides of the “booth” depict the main University building, the restored Christ the Savior cathedral, the new business district known as Moscow City, and a view of old Moscow. This cityscape happens to be based on Apollinary Vasnetsov‘s 1922 watercolor, The heyday of the Kremlin. All Saints Bridge and the Kremlin at the end of the XVII century.
If you zoom in and take a closer look at this image, you’ll see two words inked on the white wall to the right of the small white building with a triangular roof. They can be translated as “f-ck archaicity” or, less awkwardly, “down with the archaic!” As in “down with the old and up with the new.” Someone took the pains to write that, making their message visible without defacing the painted image.