Magniber Ransomware operators use PrintNightmare exploits
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2021-1675 | Remote Code Execution in Microsoft Windows Print Spooler (PrintNightmare) CVE-2021-1675 is a code execution flaw in the Windows Print Spooler service affecting the listed Windows 10, 7, 8.1, RT 8.1 and Windows Server editions. It is triggered through print operations processed by the spooler, notably print driver handling; the public PoC demonstrates DLL injection into the spooler, allowing an attacker to run arbitrary code with the privileges of the spooler service, typically SYSTEM. Successful exploitation yields full system compromise: installing programs, viewing or deleting data, creating accounts, and lateral movement into domains, which is why it has been widely used as a ransomware entry vector. Any Windows system with the Print Spooler service enabled is exposed, and the service runs by default on servers, domain controllers, and most workstations. Exploitation is confirmed in the wild: a public PoC is available, the flaw was weaponized by the Magniber and Vice Society ransomware groups, it was added to CISA KEV on 2021-11-03 with known ransomware use, and Microsoft issued out-of-band fixes after it was being exploited in the wild. Do: Apply Microsoft's out-of-band security updates immediately on all affected Windows client and server systems (per CISA KEV required action), prioritizing domain controllers and print/file servers. As an interim mitigation, disable the Print Spooler service on hosts that do not need printing (e.g., domain controllers) and restrict RPC/network access to the spooler on systems that must keep it running. Check for compromise by looking for unexpected DLL or driver files loaded by the spooler, spoolsv.exe spawning unusual child processes, and ransomware indicators given documented Magniber and Vice Society abuse. | 7.8 | 86% | KEV ransomware PoC |
| masshundreds of millions of Windows endpoints and servers (Print Spooler runs by default across the 1B+ device Windows installed base) | |
| CVE-2021-34527 | PrintNightmare: Remote Code Execution in Microsoft Windows Print Spooler CVE-2021-34527, widely known as 'PrintNightmare', is a remote code execution flaw in the Microsoft Windows Print Spooler service, which improperly performs privileged file operations such as loading printer driver DLLs. An attacker with low-level access who can reach a machine's spooler, for example a domain user able to add a printer connection via Point and Print, can induce the SYSTEM-privileged service to load an attacker-controlled DLL with no user interaction required (CVSS:3.1 vector AV:N/AC:L/PR:L/UI:N). Successful exploitation yields arbitrary code execution as SYSTEM, letting the attacker install programs, view, change or delete data, and create new accounts with full user rights, effectively achieving complete host compromise. The flaw affects all supported Windows client and server releases in the CISA data, Windows 10 from 1507 through 22H2, Windows 11, Windows RT 8.1, and Windows Server 2008, 2012 and 2016, wherever the Print Spooler service is running. Exploitation is confirmed in the wild: the bug was added to CISA's Known Exploited Vulnerabilities catalog on 2021-11-03 with known ransomware use, the FBI and CISA have warned of Russian actors exploiting it, and EPSS places the 30-day exploitation probability at 99.8%. Do: Install the July 2021 security updates immediately, released July 6, 2021 with additional updates on July 7 for Windows Server 2012, Windows Server 2016 and Windows 10 version 1607, and review KB5005010 for restricting installation of new printer drivers after applying the July 6 updates. Where patching is delayed, disable the Print Spooler service on hosts that do not need printing or restrict Point and Print, and verify that NoWarningNoElevationOnInstall and UpdatePromptSettings under HKLM\SOFTWARE\Policies\Microsoft\Windows NT\Printers\PointAndPrint are set to 0 or not defined (these keys do not exist by default, which is the secure state; NoWarningNoElevationOnInstall = 1 makes the system vulnerable by design). Prioritize domain controllers and servers with exposed spoolers, and hunt… | 8.8 | 100% | KEV ransomware PoC ×3 |
| masshundreds of millions of Windows systems (order of magnitude 10^8) | |
| CVE-2021-36958 | A remote code execution vulnerability exists when the Windows Print Spooler service improperly performs privileged file operations. A remote code execution vulnerability exists when the Windows Print Spooler service improperly performs privileged file operations. An attacker who successfully exploited this vulnerability could run arbitrary code with SYSTEM privileges. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. NVD description · AI analysis pending | 7.8 | 31% |
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Full article455 words · extracted from securityaffairs.com · click to collapse
Threat actors behind the Magniber Ransomware are using PrintNightmare exploits in attacks aimed at Windows servers.
Threat actors behind the Magniber Ransomware are exploiting the PrintNightmare flaws (CVE-2021-1675, CVE-2021-34527, and CVE-2021-36958) to infect Windows servers.
The PrintNightmare flaws reside in the Windows Print Spooler service, print drivers, and the Windows Point and Print feature.
A few hours ago Microsoft published a security advisory to warn its customers of another remote code execution zero-vulnerability, tracked as CVE-2021-36958, that resides in the Windows Print Spooler component. A local attacker could exploit the vulnerability to gain SYSTEM privileges on vulnerable systems. Microsoft said that the only workaround for this issue is to disable the Print Spooler service.
In order to address the PrintNightmare flaws, Microsoft implemented the same changes to the default Point and Print default behavior. Non-administrator users will no longer be able to do the following using Point and Print without an elevation of privilege to administrator:
- Install new printers using drivers on a remote computer or server
- Update existing printer drivers using drivers from remote computer or server
CrowdStrike recently observed malicious activity associated with Magniber ransomware, a threat that has been active since 2017. In the recent wave of attacks, the threat actors attempted to trigger the PrintNighmare vulnerability on systems belonging to victims in South Korea.
“CrowdStrike recently observed new activity related to a 2017 ransomware family, known as Magniber, using the PrintNighmare vulnerability on victims in South Korea. On July 13, CrowdStrike successfully detected and prevented attempts at exploiting the PrintNightmare vulnerability, protecting customers before any encryption takes place.” reads the post published by CrowdStrike.
The experts discovered that once compromised a server exploiting a PrintNightmare flaw, Magniber drops an obfuscated DLL loader, then injects it into a process and later unpacks the DLL loader to perform local file traversal and encryption on the infected system.
The ransomware drops a ransom note that does not reveal anything about the ransomware operators, it only provides instructions to contact the threat actors for negotiation.
According to BleepingComputer, Magniber’s activity spiked in the last 30 days, experts reported almost 600 submissions on the ID Ransomware platform.
Researchers believe that other ransomware gangs will start using PrintNightmare exploits in their operations.
“CrowdStrike estimates that the PrintNightmare vulnerability coupled with the deployment of ransomware will likely continue to be exploited by other threat actors. We encourage organizations to always apply the latest patches and security updates to mitigate known vulnerabilities and adhere to security best practices to strengthen their security posture against threats and sophisticated adversaries.” CrowdStrike concludes.
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Text extracted automatically; images, tables and formatting may be missing. Original: https://securityaffairs.com/121076/malware/magniber-ransomware-printnightmare-exploits.html