The hackers behind a sophisticated attack campaign that has recently targeted financial organizations around the world have intentionally inserted Russian words and commands into their malware in an attempt to throw investigators off.

Researchers from cybersecurity firm BAE Systems have recently obtained and analyzed additional malware samples related to an attack campaign that has targeted 104 organizations -- most of them banks -- from 31 different countries.

They found multiple commands and strings in the malware that appear to have been translated into Russian using online tools, the results making little sense to a native Russian speaker.

"In some cases the inaccurate translations have transformed the meaning of the words entirely," the researchers said in a blog post. "This strongly implies that the authors of this attack are not native Russian speakers and, as such, the use of Russian words appears to be a 'false flag'."

This unusual behaviour is most likely intended to make attribution harder and throw investigators on a false lead. In reality there is technical evidence to link these malware samples and the overall attack campaign to a group known in the security industry as Lazarus.

This group has been active since at least 2009 and has been responsible for various attacks against government and private organizations from South Korea and the U.S. over the years.

Lazarus is believed to have been responsible for the 2014 attack against Sony Pictures Entertainment that resulted in sensitive data being leaked from the company and many of the company's computers being rendered inoperable. The FBI and other U.S. intelligence agencies attributed that attack to North Korea.

The Lazarus group has also been linked to the theft of US$81 million from the central bank of Bangladesh last year. In that attack, hackers used malware to manipulate the computers used by the bank to operate money transfers over the SWIFT network. They attempted to move $951 million in total, but some transactions failed and others were successfully reversed after the heist was detected.

Earlier this month a malware attack that affected multiple banks in Poland came to light. The attack is believed to have involved exploits launched from the compromised website of the Polish Financial Supervision Authority.

Researchers from BAE Systems and Symantec have tied the Polish attack to a larger campaign that has been going on since October and involved multiple watering-hole-style compromises. The websites of the National Banking and Stock Commission of Mexico and the largest state-owned bank from Uruguay have also been infected in a similar manner.

The malware programs used in these attacks bear code similarities to tools attributed in the past to the Lazarus group.

There are several cybercriminal gangs of Russian origin that specialize in targeting banks. These groups use spear-phishing to gain a foothold into banks' networks and then learn the organizations' internal procedures before they begin to steal money. BAE Systems' research suggests that Lazarus might be trying to make its activity blend in with that of these Russian-speaking cybercriminals.