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MEGAsync is a legitimate cloud synchronization client for the MEGA file-sharing service that has been repeatedly abused by ransomware and extortion actors as an exfiltration utility rather than as a malicious payload in its own right. In intrusion and double-extortion operations, attackers use MEGAsync to transfer stolen data to MEGA-hosted storage before or alongside ransomware deployment, enabling extortion based on threatened public release of sensitive information.
Its observed role is primarily in post-compromise data theft workflows. Threat actors have used MEGAsync after establishing access, conducting reconnaissance, obtaining credentials, and moving laterally within victim environments. Reported cases tie its abuse to ransomware ecosystems including Nefilim, LockBit, Hades, BlackCat/ALPHV, and NoEscape, where it has appeared alongside other dual-use tools such as Rclone, PsExec, Mimikatz, AdFind, and remote administration utilities. In BlackCat intrusions, exfiltration with MEGAsync has been observed after enterprise discovery and credential theft activity. In NoEscape-related incident response reporting, MEGAsync was used to exfiltrate data to cloud storage during a broader Exchange-compromise-to-ransomware intrusion chain.
Because MEGAsync is legitimate software, its presence alone is not inherently malicious and can complicate detection when adversaries rename binaries or blend usage with normal administrative or user activity. High-confidence reporting supports classifying it as an attacker-abused exfiltration tool associated with ransomware operations, especially double-extortion campaigns targeting enterprise Windows environments.
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13 distinct techniques documented for this family, organized by ATT&CK tactic.
adversaries rarely execute tools like MegaCmd or MegaSync under their original filename... you might achieve a good detection outcome by identifying processes based on metadata like their internal name and then alerting when the internal name and the presented process name do not match.
In some instances, adversaries will execute MegaSync under its real name but from an unusual installation path. A detection analytic for identifying relocated copies of MegaSync execution may look something like this: Binary named megasync.exe File execution path does not include AppData\\Local\\MEGAsync\\
A few days later, once the actors got a firm foothold on the network, they used MEGAsync to exfiltrate more than 25 gigabytes of data.
The Beast operator was found to use a tool called MEGASync for data exfiltration before encryption; this tool helps automatically upload large volumes of data to the cloud storage service Mega[.]nz.
The data was exfiltrated over a 90-minute period, likely via the StealBit tool, prior to execution of the ransomware.
Adversaries may steal data by exfiltrating it over a different protocol than that of the existing command and control channel.
MITRE ATT&CK T1048.003 – Exfiltration Over Alternative Protocol: Exfiltration Over Unencrypted/Obfuscated Non-C2 Protocol
INC Ransom has used Megasync to exfiltrate data to the cloud.
4 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Legitimate cloud sync client abused for data exfiltration to Mega as part of a double-extortion ransomware workflow.
Legitimate cloud sync client referenced as being used for data exfiltration over web services during intrusions.
MEGA client abused for bulk data exfiltration in BlackCat-related intrusions to support double extortion.
Cloud synchronization client abused for data exfiltration in double-extortion ransomware operations, enabling rapid upload and storage of stolen files.
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Named campaigns wielding this family, with evidence pinned to each claim.
CVEs this family uses for access and lateral movement.
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Every documented technique, ranked by evidence weight.
Reddit, Mastodon, and CTI community discussion around this family.