Venmo, Zelle, Cash App leaving users vulnerable to fraud: Manhattan DA

Venmo, Zelle and Cash App are leaving consumers vulnerable to fraud that's "draining bank accounts of significant sums of money," Manhattan District Attorney Alvin Bragg said in letters to the companies that own those financial apps. He demanded they increase protections.

Bragg's letters said he was writing "in response to a growing number of incidents" involving fraud and theft "through the exploitation of your company's mobile financial applications on personal electronic devices such as iPhones."

Peer-to-peer payment services now handle an estimated $1 trillion in payments and the district attorney said "frauds and scams have proliferated" as usage climbs.

In the past year, there have been thefts stretching from Los Angeles, where several people were robbed of thousands of dollars through Venmo at knifepoint, to Orlando, where a woman had thousands drained from her Venmo after a child asked to use her phone. Similar thefts and robberies have been publicly reported in West Virginia, Louisiana, Illinois, Kansas, Tennessee, Virginia and elsewhere across the United States.

"These crimes involve an unauthorized user gaining access to unlocked devices and then draining bank accounts of significant sums of money, making purchases with mobile financial applications, and using financial information from the applications to open new accounts," Bragg's letters said. "Offenders also take over the phone's security by changing passwords, recovery accounts, and application settings. The ease with which offenders can collect five- and even six-figure windfalls in a matter of minutes is incentivizing a large number of individuals to commit these crimes, which are creating serious financial, and in some cases physical, harm to our residents."

The district attorney called on Venmo, Zelle and Cash App to adopt additional security measures, including imposing limits on transactions, requiring secondary verification of up to a day and better monitoring of unusual activity.

"I am concerned about the troubling rise in illegal behavior that has developed because of insufficient security measures connected with your software and business policy decisions," Bragg's letters said.

He is requesting meetings with the companies.

Reacting to the Manhattan DA's comments, a spokesperson for Early Warning Services, LLC, the network operator of Zelle, said the company was "aware of isolated criminal incidents" described in the Manhattan District Attorney's letter.

"Providing a safe and reliable service to consumers is the top priority of Early Warning Services, LLC, the network operator of Zelle, and our 2,100 participating banks and credit unions," the statement continued. " As a result of our continued efforts to build on Zelle's strong foundation of security, less than one tenth of one percent of transactions are reported as fraud or scams, and that percentage keeps getting smaller."

In the statement, the spokesperson said its network's "participating financial institutions are required to reimburse consumers for confirmed fraud claims. Consumers should contact the local authorities and their bank and credit union if they were a victim of a crime to begin the claims process."

In a statement, a spokesperson for Cash App said it continues to be "committed to building trust with our customers and investing in areas that help build a safe and secure platform."

"We work proactively and diligently to safeguard our customer's money and mitigate against the risk of fraud on our platform through a combination of preventative controls like multi-factor authentication, account transaction limits, fraud detection, and consumer education. We also partner with law enforcement agencies to detect and combat criminal activity," the statement said.

PayPal did not immediately respond to ABC News' request for comment.