An analysis of incidents at Brazilian educational institutions

Introduction Because of the amount of data that can be obtained and the high impact that successful attacks may have, educational institutions are frequent targets of cybercriminals. Both public and private schools and universities rely on software for managing personally identifiable information (PII) that is often insecure or insufficiently tested against known vulnerabilities. In addition, machines used by multiple people without accountability can be vulnerable to insider threats. The complexity of academic environments amplifies this risk. Unlike corporate networks, educational institutions have to provide a network that supports students, professors, researchers, administrative staff, third-party contractors, and visitors. Each of these groups has different security requirements and access control levels, making it difficult to enforce consistent security policies. A security breach can have severe consequences since it may expose vast amounts of sensitive information, such as social security numbers (CPF in Brazil), addresses, phone numbers, and even parents’ names. Armed with this information, attackers can attempt phishing attacks and impersonate the victims in SIM swapping attacks, a common practice in Brazil. In this article, we provide details about attacks on educational institutions in Brazil observed by our Global Emergency Response Team (GERT) since 2025. We share general statistics, common threats, initial access vectors, and the impact of such violations. Additionally, we present some interesting cases encountered by our team and the identified TTPs. Finally, we offer recommendations to help institutions protect themselves against future attacks. Key findings and statistics Our dataset encompasses incident response cases from January 2025 to June 2026. As the chart below shows, the majority of attacks targeted institutions in São Paulo state, Brazil’s most populous state and a significant center of economic and financial activity. We also had cases in Rio de Janeiro and Pernambuco. Geographical distribution of incident response requests at educational institutions (download) Of the customers who requested incident response, 60% were private institutions and 40% were public institutions. Private and public institutions (download) The most frequent reasons for requesting IR services were related to suspicious endpoint activities, encrypted files, and the presence of suspicious files. Incident response request reasons (download) High-severity incidents accounted for 40% of the total cases, while the remaining 60% were medium severity. Distribution of incidents by severity (download) The high-severity incidents were mainly related to ransomware attacks. Interestingly, private institutions were the most targeted by ransomware, while incidents in public institutions were mostly related to suspicious endpoint activity and privilege escalation attempts. The most common ransomware families found in our dataset were DragonForce and LockBit 3, whose builder was leaked back in 2022. By using the leaked LockBit builder with a valid privileged account, attackers can build variants capable of disabling defenses and erasing logs. The most common initial access vectors included the use of valid accounts, exploitation of public-facing applications, and insiders. Initial access vectors (download) For privilege escalation, the attackers often relied on Potato variants (GodPotato, SweetPotato, and BadPotato). We also observed attackers using tools like AnyDesk for remote access, PsExec for lateral movement within compromised infrastructures, and AV-killer malware to terminate the system’s defenses. The latter was mainly used in ransomware-related incidents. These data reveal an interesting pattern in the threat landscape affecting educational institutions in the region. Many incidents were not caused by highly sophisticated techniques but rather by the abuse of common weaknesses such as valid accounts, exposed applications, and inadequate patch management, as well as the use of publicly available tools that are well-known to the adversaries. The prevalence of ransomware in private institutions suggests a stronger financial motivation, likely because attackers assume these organizations are more capable of paying for data recovery than public schools and universities. Most attacks were discovered promptly and lasted from a few minutes to a couple of hours. However, technical incident response activities averaged 9.6 hours. This indicates that the impact caused by an incident often extends beyond the timeframe of the active attack, requiring extensive triage and analysis by the forensic investigators to fully restore operations. One interesting fact is that we are still observing the use of Windows 10 in the infrastructures of educational institutions, even after Microsoft’s official end-of-support date of October 2025. In addition, we found that some customer organizations were using Windows Server 2016 without security patches and fixes. Using outdated and unsupported operating systems increases the attack surface of an infrastructure because attackers can exploit publicly available vulnerabilities to access vulnerable systems and expand their presence in the network. In addition, legacy operating systems may be incompatible with modern evidence collection tools, necessitating extra time and alternative procedures for forensic acquisition. Obsolete systems in organizations (download) Interesting cases Case 01 – Leaked LockBit builder In one case, we identified the use of a custom version of LockBit that was generated using the leaked builder. The ransomware was delivered to the organization’s infrastructure via a valid account that had been leaked. It encrypted the organization’s internal systems, including file servers and databases that stored student profiles and other data. There was no evidence of data exfiltration from the affected machines. During our analysis of the LockBit sample, we were able to extract its configuration. Interestingly, it was configured without the impersonation and spreading options. This meant the attacker had to perform manual lateral movement to deploy the malware across the network. | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 | "config": { "settings": { "impersonation": false, "local_disks": true, "network_shares": true, "kill_processes": true, "kill_services": true, "set_wallpaper": true, "self_destruct": true, "kill_defender": true, "wipe_freespace": true, "psexec_netspread": false, "gpo_netspread": false, … | Further analysis revealed that the attacker used PsExec for lateral movement. By analyzing the Update Sequence Number (USN) Journal, we were able to identify .KEY files associated with PsExec that showed us the previously compromised machines used by the attacker. After gaining access to the target machines, the adversaries deployed a batch script to disable the system’s defenses. Our analysis of this artifact showed that they had the administrative credentials to disable the EDR in place. In addition, the script enabled RDP, which gave the attackers remote access to the target. The listing below shows an excerpt of the script: | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 | reg add "HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server" /v fDenyTSConnections /t REG_DWORD /d 0 /f netsh advfirewall firewall add rule name="allow RemoteDesktop" dir=in protocol=TCP localport=3389 action=allow reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows Defender" /v DisableRealtimeMonitoring /t REG_DWORD /d 1 /f reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows Defender\Real-Time Protection" /v DisableBehaviorMonitoring /t REG_DWORD /d 1 /f reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows Defender\Real-Time Protection" /v DisableOnRealTimeProtection /t REG_DWORD /d 1 /f reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows Defender\Real-Time Protection" /v DisableIOAVProtection /t REG_DWORD /d 1 /f reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows Defender\Real-Time Protection" /v DisableScriptScanning /t REG_DWORD /d 1 /f reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows Defender\Spynet" /v SpyNetReporting /t REG_DWORD /d 0 /f reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows Defender\Spynet" /v SubmitSamplesConsent /t REG_DWORD /d 2 /f reg add "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run" /v "SecurityHealth" /t REG_SZ /d "" /f reg delete "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\MyComputer\NameSpace\{UUID}" /f reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows Defender" /v ServiceKeepAlive /t REG_DWORD /d 0 /f sc stop WinDefend sc config WinDefend start= disabled | Finally, by cross-checking the Prefetch files, we were able to identify the precise dates of PsExecSvc.exe and LBB.exe (LockBit) execution. This revealed that the attacker established the initial connection to the analyzed machine around 5:30am UTC and ran LBB.exe for the last time at 10am UTC on the same day, resulting in an activity window of approximately four hours and thirty minutes. We were able to identify the extent of the compromise and the additional machines that required network isolation for further forensic analysis, containment, and remediation. Case 02 – DragonForce deployed via AnyDesk In another incident, we identified a compromised user account that the adversaries used to install the AnyDesk software to enable remote access. Although the attacker erased the system logs after encrypting the victim’s files, we were able to identify the ransomware execution event via the Prefetch and Amcache.hve files, which provided us with the SHA-1 hash of the sample. Once we obtained the SHA-1 of the malicious artifact (named by the attacker as 1.EXE ), we were able to confirm that it was a DragonForce variant. Even though the lack of evidence made the analysis more difficult, this case shows that forensic investigators must be prepared to identify information that the attackers missed or left untouched. Case 03 – Python keylogger used by an insider The third incident illustrates how a series of bad practices enabled an insider to collect passwords from other users inside the infrastructure. First, the customer contacted us stating that a machine was exhibiting strange behavior: files containing passwords were being created. We started with triage collection on one of the affected machines. Evidence from the Program Compatibility Assistant (PCA) showed the execution of two suspicious files, Windows Host Widgets.exe and Windows Host Widgets_.exe , both located in the C:\Users\\.vscode\dlo directory, where represents a user account shared by everyone who uses the machine. The same artifacts were identified within the Amcache.hve file, and multiple executions were also confirmed by analyzing the Prefetch files. Another interesting source of evidence, UserAssist, confirmed that the threat actor also executed both EXE files by double-clicking on them. MFT analysis showed that multiple log files named cacheX.txt were created in the previously mentioned directory, where X was a number that increased with each malware execution. We then analyzed the EXE files to confirm their behavior. Luckily, both proved to be the same Python script, which we could easily decompile. As shown in the listing below, the script contains methods and strings with Portuguese names. It is capable of hiding the log files from view in Explorer. The developer also set a procedure to identify when the Caps Lock key was pressed, in order to record the correct passwords. | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 | def get_base_path(): ... def encontrar_proximo_nome(base='cache'): ... def set_file_hidden(filepath): ... ctypes.windll.kernel32.SetFileAttributesW(str(filepath), FILE_ATTRIBUTE_HIDDEN) ... with open(log_file, 'a', encoding='utf-8') as f: f.write(f'\n\n--- Registro iniciado em {datetime.datetime.now()} ---\n') set_file_hidden(log_file) ... def is_capslock_on(): return bool(ctypes.windll.user32.GetKeyState(20) & 1) ... def on_press(key): ... def on_release(key): ... def main(): with keyboard.Listener(on_press=on_press, on_release=on_release) as listener: listener.join() if __name__ == '__main__': main() | This simple script did not implement any persistence or automated data exfiltration mechanisms. Therefore, the insider likely had to manually retrieve the generated log files containing the text typed by the victims. By revisiting the previously collected evidence, we identified USB connections around the same time as the script’s executions. This suggests that removable media was probably used to collect the generated keylogging logs from the environment. As a result of the investigation, the customer changed the passwords of all affected accounts. However, without additional evidence or footage, it was not possible to conclusively attribute the activities to a specific individual and take the appropriate disciplinary and legal measures. Conclusions and recommendations The incidents highlighted in this article demonstrate that Brazilian educational institutions face a diverse set of threats, ranging from ransomware operations to insider activity. In many cases, the attackers relied on valid credentials, exposed services, remote access tools, poor patch management, and insufficient endpoint hardening rather than advanced malware or new techniques. Based on these findings, educational institutions should prioritize controls that reduce the likelihood of account compromise and the impact of ransomware deployment. They should also improve forensic visibility after an incident. Institutions should enforce the use of multi-factor authentication (MFA) for all publicly accessible services, especially VPNs, remote access portals, and email accounts. Since valid accounts were one of the most common initial access vectors observed in our dataset, MFA can significantly reduce the likelihood that stolen or reused credentials alone will compromise the entire environment. We also recommend periodically reviewing privileged accounts, removing unnecessary administrative permissions, and avoiding shared accounts, especially on machines accessed by multiple users, since this makes accountability extremely difficult. Each user should have their own account, following the principle of least privilege to prevent unauthorized software execution. Additionally, it is advisable to restrict and monitor the use of remote access tools such as AnyDesk or TeamViewer. Unexpected installations or executions of these tools should be treated as high-priority alerts. To minimize the impact of ransomware, educational institutions should improve their backup and recovery strategy. Backups should be isolated from the primary environment (preferably in more than one location) and tested regularly. Centralized logging, extended EDR telemetry retention, and proper time synchronization across hosts can also improve the ability to reconstruct an attack timeline and implement the necessary response measures. The use of outdated systems increases the attack surface, so we recommend that organizations adopt an effective update and patch management policy. It is also important to raise security awareness, since users must understand the risks associated with credential sharing, unknown executables, and unauthorized software. From a digital forensics and incident response (DFIR) perspective, the reviewed incidents demonstrate that effective incident response activities require correlating multiple forensic artifacts in order to reconstruct the attacker’s actions. Investigators should be aware of how to find information even when logs are missing. Many other artifacts are preserved and can be used for this purpose, such as Amcache, PCA, Prefetch, UserAssist, MFT, and USN Journal. The attackers may fail to erase all traces of their activity, so taking a broad forensic approach is of the utmost importance for determining the scope of the compromise and supporting containment and remediation actions. Observed TTPs The table below shows the observed TTPs in our dataset, including cases not detailed in this post. | Tactic | Technique | ID | | Resource Development | Compromise Accounts | T1586 | | Collection | Input Capture: Keylogging | T1056.001 | | Execution | System Services: Service Execution | T1569.002 | | Execution | Hijack Execution Flow: DLL | T1574.001 | | Privilege Escalation | Exploitation for Privilege Escalation | T1068 | | Lateral Movement | Remote Services: Remote Desktop Protocol | T1021.001 | | Command and Control | Remote Access Tools | T1219 | | Exfiltration | Exfiltration over Physical Medium: Exfiltration over USB | T1052.001 | | Impact | Data Encrypted for Impact | T1486 | An analysis of incidents at Brazilian educational institutions