A chain is no stronger than its weakest link , What happens when the chain ,in this case the "supply chain" itself is weak? - "Supply Chain Attack"

Wipro Ltd. has confirmed that its network was hacked and used for mounting attacks on its customers.

“[Victims] traced malicious and suspicious network reconnaissance activity back to partner systems that were communicating directly with Wipro’s network,” according to the sources. 

The incident is emblematic of the new era of highly targeted supply-chain attacks that have begun to accelerate.

https://threatpost.com/wipro-confirms-hack/143826/