CVE-2011-2662 in GroupWise
Summary
by MITRE
Integer signedness error in GroupWise Internet Agent (GWIA) in Novell GroupWise 8.0 before HP3 allows remote attackers to execute arbitrary code via a negative BYWEEKNO property in a weekly RRULE variable in a VCALENDAR attachment in an e-mail message.
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Analysis
by VulDB Data Team • 11/23/2021
The vulnerability identified as CVE-2011-2662 represents a critical integer signedness error within Novell GroupWise 8.0 before HP3's GroupWise Internet Agent component. This flaw exists in the processing of iCalendar (RFC 2445) formatted calendar data that is embedded within email messages. The vulnerability specifically manifests when the GWIA encounters a malformed VCALENDAR attachment containing a weekly recurrence rule with a negative BYWEEKNO property value. This condition creates a scenario where the application fails to properly validate the signedness of integer values during calendar data parsing, leading to potential memory corruption and arbitrary code execution.
The technical exploitation of this vulnerability occurs through a carefully crafted email message containing a malicious VCALENDAR attachment. When the GroupWise Internet Agent processes this attachment, it attempts to parse the RRULE component with a negative BYWEEKNO value, which triggers the integer signedness error. This error causes the application to interpret negative integer values as positive ones during memory allocation or array indexing operations, potentially resulting in buffer overflows or other memory corruption conditions. The vulnerability falls under CWE-190, Integer Overflow or Wraparound, and specifically relates to CWE-191, Integer Underflow, as the negative values cause unexpected behavior in signed integer operations. This flaw is particularly dangerous because it enables remote code execution without requiring authentication, making it a prime target for automated attacks.
The operational impact of CVE-2011-2662 is severe and far-reaching within organizations utilizing Novell GroupWise 8.0 systems. Attackers can leverage this vulnerability to gain unauthorized access to email servers, potentially escalating privileges to system-level access depending on the execution context. The remote nature of the exploit means that attackers can target users from outside the organization, making traditional network perimeter defenses insufficient for protection. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under T1190, Exploit Public-Facing Application, and T1059, Command and Scripting Interpreter, as successful exploitation could enable attackers to execute arbitrary commands on the affected systems. Organizations with extensive GroupWise deployments face significant risk of data breaches, system compromise, and potential lateral movement within their networks.
Mitigation strategies for CVE-2011-2662 should focus on immediate patching of affected systems, as Novell released security updates to address this specific vulnerability. Organizations should implement email filtering solutions that can detect and block malformed calendar attachments, particularly those containing iCalendar data with suspicious RRULE components. Network segmentation and access controls should be enforced to limit exposure of GroupWise servers to untrusted networks. Security monitoring should include detection of unusual email processing patterns and potential exploitation attempts. Additionally, administrators should disable unnecessary calendar functionality and implement strict validation of all calendar data received through email. The vulnerability demonstrates the importance of proper input validation and integer handling in security-critical applications, emphasizing that developers should employ defensive programming practices to prevent similar issues in future implementations. Organizations should also consider implementing email security appliances that can sanitize calendar data before it reaches the GroupWise server, providing an additional layer of protection against similar vulnerabilities.