Description
A critical vulnerability has been identified in the Print Spooler service of Microsoft Windows, which affects several versions including Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP1 and SP2, Windows Server 2008 Gold, SP2, and R2, along with Windows 7. This vulnerability allows remote attackers to create files in a system directory and execute arbitrary code through a crafted print request over the RPC protocol. Referred to as the “Print Spooler Service Impersonation Vulnerability,” this was notably exploited in the wild in September 2010.
Affected Product(s)
Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP1 and SP2, Windows Server 2008 Gold, SP2, and R2, and Windows 7.
Technical Details
The vulnerability, with a CVSSv3 score of 9.8 (Critical) and CVSSv2 score of 9.3 (High), pertains to Microsoft’s Print Spooler service, which manages print jobs by storing them in a queue and sending them to the printer when resources are available. The flaw arises from the service’s failure to properly validate access permissions, making it susceptible to service impersonation.
When exploited, this vulnerability allows an unauthenticated remote attacker to create files in a system directory by sending a specially crafted print request via the RPC protocol. The attacker can then execute arbitrary code on affected systems, leading to potential privilege escalation.
This security weakness falls under CWE-20: Improper Input Validation and CWE-284: Improper Access Control. The vulnerability became widely known following its use by the Stuxnet worm, a sophisticated piece of malware discovered in 2010. Stuxnet targeted specific industrial control systems and exploited four zero-day bugs, including CVE-2010-2729. The worm had a notable impact on Siemens’ SCADA systems and used these vulnerabilities to spread and compromise targeted environments. Stuxnet’s association with CVE-2010-2729 emphasized the severe risk of this vulnerability, especially in industrial and enterprise settings.
Additionally, the vulnerability was part of a disclosure by a hacking group known as the Shadow Brokers, which made the exploits public in 2017, associating it with EMERALDTHREAD among many vulnerabilities attributed to the Equation Group. The Print Spooler vulnerability was documented in Microsoft Security Bulletin MS10-061.
Microsoft addressed the vulnerability through a security update that revised how the Print Spooler service validates user permissions. Despite the release of patches, the broader use and exploitation of this vulnerability, particularly in malware attacks like Stuxnet, highlighted significant concerns about securing legacy systems and critical infrastructure against sophisticated threats.
Weakness
The primary weakness associated with this vulnerability is Improper Input Validation (CWE-20) combined with Improper Access Control (CWE-284). These issues allow remote unauthenticated access to system services resulting in unauthorized file creation and potential code execution on the target system.
Impact Assessment
If exploited, this vulnerability could allow an attacker to gain unauthorized access to sensitive data and execute arbitrary code on the affected system, escalating their privileges and potentially leading to complete system compromise and beyond, such as infecting networked environments with malware.
Active Exploitation
We have observed activity from the adversary group known as Shadow Brokers, who disclosed this vulnerability alongside others attributed to the Equation Group, famously associated with sophisticated cyber espionage and offensive operations. Notably, the Stuxnet worm exploited this vulnerability, and there are known exploits in circulation for targeted attacks.
Threat Actors: The Equation Group is known for leveraging this vulnerability, as revealed by the Shadow Brokers group.
Ransomware Association
While there is no direct documented association of CVE-2010-2729 with specific ransomware attacks, its exploitation in deploying highly targeted and impactful malware like Stuxnet highlights its potential for misuse in varied cyber threat scenarios, including ransomware, due to its capability for remote code execution and system compromise.
Mitigation and Resolution
Microsoft released a security update (MS10-061) addressing this vulnerability by correcting the manner in which the Print Spooler service validates user permissions. Users are advised to apply this patch immediately to protect against potential exploitation. Additionally, disabling printer sharing unless necessary can mitigate exposure risk.
Recommendations
- We strongly recommend that all customers apply the latest patch MS10-061 as soon as possible.
- Ensure that printer sharing is disabled unless absolutely necessary, especially on systems connected to sensitive or critical networks.
- Regularly review and update security controls and patch management policies to include all networked systems and devices.
- Consider segmenting network zones and implementing strict access controls to limit exposure and potential lateral movement.
- Conduct security awareness training to educate users on recognizing and reporting suspicious activities related to print services.
- Employ network-based intrusion detection systems to alert on anomalies associated with unexpected print job activities.
ย References
- Zero Day Database
- Microsoft Security Bulletin
- CVE MITRE
- National Vulnerability Database
- Stuxnet Vulnerability Analysis of SCADA Systems
- Stuxnet – SCADA Malware Research
- New Exploits to Metasploit CVE-2010-2729
- Printlove Removal Report
- Stuxnet: Pushing the Cyberwarfare Envelope
- CISecurity Repository
- Kaspersky Security Bulletin 2010
- McAfee Stuxnet Update
- NSE Support Scripts
- Microsoft Technet Library
- Symantec Security Response
- Virus Bulletin: Indepth Look at Stuxnet