DMARC is targeted by hackers as this serves to act as a preventative measure against email spoofing and phishing attempts.  They compromise DMARC (Domain-based Message Authentication Reporting and Conformance) so that they can evade email authentication protocols, consequently enabling them to mimic authentic senders and mislead recipients.  This way they can put up more conceivable and advantageous phishing campaigns that lead to either making money or stealing data. Cybersecurity researchers at ProofPoint recently discovered that North Korean hackers are actively abusing the DMARC to legitimize their illicit emails.

Source: GBHackers