The group, whose attack campaigns have been investigated by researchers working with Citizen Lab at the University of Toronto's Munk School of Global Affairs, has been dubbed Packrat. It appears mainly interested in political opposition groups and influential people from countries like Argentina, Ecuador and Venezuela.
While there is insufficient evidence to link the group to a particular government or intelligence agency, the researchers believe "that the ultimate recipient of the information collected by Packrat is likely one or more governments in the region."
The group commonly uses politically themed phishing emails to distribute commercial RATs to their intended targets, which have included high-profile Argentine prosecutor Alberto Nisman, investigative journalist and television host Jorge Lanata and reportedly Maximo Kirchner, the son of former Argentine presidents Néstor Kirchner and Cristina Fernández de Kirchner.
There is evidence from file compilation dates and command-and-control infrastructure to suggest that between 2008 and 2013 the group targeted individuals from Brazil. However, the Citizen Lab researchers couldn't identify or confirm any victims from that period.
By 2014, the group had moved to targeting influential people from Argentina and also started campaigns against targets from Ecuador and Venezuela. The researchers found evidence of malware attacks this year against public figures from Ecuador.
In addition to infecting computers with malware, the group also created fake online political opposition movements and organizations that were likely used for disinformation in Ecuador and Venezuela.
Over the years, the group has used several RATs in their attacks, including CyberGate, XTreme RAT, AlienSpy and Adzok. The Citizen Lab researchers connected the attacks to a single group after finding strong correlations between their command-and-control infrastructures.
While the malware used in one of the attacks was being analyzed, one of the attackers started leaving taunting and threatening messages in Spanish on the test system used by researchers. These messages included: "We are going to analyze your brain with a bullet and your family too;" "You like playing the spy where you shouldn’t, you know it has a cost, your life;" "We have your picture;" and "Take care of your family."
"Packrat highlights the extent to which multi-year campaigns can be run using limited technical sophistication, and a lot of creativity," the researchers said in their analysis report. "From a technical perspective, they rely almost entirely on off-the-shelf RATs and packers to evade antivirus detection. Where they excel is in the time and effort spent to create detailed and moderately convincing fake organizations to seed their malware."