Is it permissible to make an analogy based on a concession to derive another concession, such as the permissibility of wiping over the socks commonly known nowadays, even though the narrations regarding wiping only mentioned the khuffayn (leather slippers)?

Wiping over socks made of material other than leather, such as wool and the like, is permissible. The Prophet, peace and blessings be upon him, performed ablution and wiped over his socks and sandals. A group of companions also did this, including Ali, Ammar, Ibn Mas'ud, Anas, Ibn Umar, Al-Bara', Bilal, Ibn Abi Awfa, and Sahl bin Sa'd.

This issue is one of juristic ijtihad (definition), and the preponderant opinion is the permissibility of wiping over socks due to the hadith (definition) on the matter and the actions of the Companions.