Researchers from security outfit Flashpoint said in a blog post on Wednesday that it appeared infrastructure from the earlier attacks had been re-used.
There is no public statement on Wipro's site about the breach even though it came to light on 15 April, through a report on the blog Krebsonsecurity.
Flashpoint's Jason Reaves, Joshua Platt and Allison Nixon wrote that a number of legitimate security applications had been abused during the attack.
"The attackers also dropped ScreenConnect on the machines it compromised inside Wipro, and some of the domains used in the attack were hosting Powerkatz and Powersploit scripts."
They described ScreenConnect as a remote access tool that could be used in support engagements or for remote meetings.
"Powerkatz is a PowerShell version of Mimikatz, a post-exploitation tool that is able to search memory for credentials, tokens, and other artefacts related to authentication," the trio said. "Powersploit, meanwhile, is a collection of PowerShell modules used during penetration-testing engagements to launch exploits at a target."
Flashpoint found that about half a dozen of the malicious domains and IP addresses were phishing domains hosting templates that were used for credential phishing attempts, seeking victims’ Windows usernames and passwords in order to allegedly access encrypted email.
Reaves, Platt and Nixon also found evidence of attempts by the attackers to spread a remote administration tool known as Imminent Monitor.
"Flashpoint was able to pivot off the file name and locate other campaigns associated with the activity, in particular a hash which led to a Word document containing a message and attachment matching the naming structure of a campaign in 2017," they wrote.
Asked for its take on the issue, a Wipro spokesperson told iTWire: "Wipro can confirm that it was among the targets of a co-ordinated and advanced phishing campaign reportedly directed against several companies. As soon as we became aware of the campaign, we began an investigation, identified potentially affected users, promptly informed the customers with whom these employees were engaged and began taking remedial steps to contain and mitigate any potential impact.
"We have applied additional security measures to further strengthen our systems and continue to monitor our enterprise infrastructure at a heightened level of alertness. We have engaged an independent forensic firm to assist us in the investigation while our partners in the security domain who have an understanding of our operations are supporting us in the remediation efforts. The investigation is ongoing and we don't have any further comments to offer at this point in time."