Financial mobile apps come with large numbers of vulnerabilities stemming from a dangerous lack of security controls and insecure coding practices. 97% of the total number of apps were easily reverse engineered or decompiled because they lacked binary code protection. 90% allowed their data to be shared with other applications installed on the same device via shared services. 80% of examined Android apps as part of the experiment were found be using either weak encryption algorithms or incorrect implementations of strong ciphers thus making it easy for malicious actors to decrypt and steal sensitive information.
Source: https://www.bleepingcomputer.com/news/security/financial-mobile-apps-fail-to-follow-proper-security-standards/