CVE-2018-7194 in osTicket
Summary
by MITRE
Integer format vulnerability in the ticket number generator in Enhancesoft osTicket before 1.10.2 allows remote attackers to cause a denial-of-service (preventing the creation of new tickets) via a large number of digits in the ticket number format setting.
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Analysis
by VulDB Data Team • 01/17/2020
The CVE-2018-7194 vulnerability represents a critical integer format issue within the ticket number generator component of Enhancesoft osTicket versions prior to 1.10.2. This flaw exists in the application's handling of ticket number format settings, where the system fails to properly validate or sanitize input values that contain excessive numeric digits. The vulnerability stems from inadequate input validation mechanisms that allow malicious actors to submit malformed ticket number formats containing an excessive number of digits, which can subsequently disrupt the application's normal operational flow.
The technical implementation of this vulnerability exploits the underlying integer parsing and formatting routines within the osTicket application. When administrators configure ticket number formats, the system processes these settings through internal functions that do not properly handle edge cases involving extremely large numeric values. This weakness creates a scenario where the application's ticket generation logic becomes unstable when encountering format strings with thousands of digits, leading to arithmetic overflow conditions or memory allocation failures within the integer handling subsystem. The vulnerability specifically targets the application's inability to properly validate user-supplied format strings against reasonable numeric constraints, creating a path for attackers to manipulate the system's internal state.
Operationally, this vulnerability enables remote attackers to execute denial-of-service attacks against osTicket installations by manipulating the ticket number format configuration. The impact manifests as complete prevention of new ticket creation functionality, effectively rendering the support system unusable for legitimate users. Attackers can exploit this weakness by submitting a format string containing an excessive number of digits, causing the application to enter an unstable state where it cannot properly generate or process ticket numbers. This disruption affects not only the immediate ticket creation process but can also impact related functionality such as ticket numbering consistency and system resource management. The vulnerability is particularly concerning because it can be exploited without authentication requirements, making it accessible to any remote attacker with knowledge of the target system.
The vulnerability aligns with CWE-190, which describes integer overflow and arithmetic overflow conditions, and demonstrates how improper input validation can lead to system instability. From an adversarial perspective, this flaw maps to ATT&CK technique T1499.004, which covers network disruption through resource exhaustion or system instability. Organizations running affected versions of osTicket face significant operational risks as attackers can systematically prevent legitimate ticket creation while maintaining persistence in the system. The vulnerability's impact extends beyond immediate service disruption to potentially compromise the entire support infrastructure, affecting customer service operations and business continuity.
Mitigation strategies should focus on immediate patching of affected osTicket installations to version 1.10.2 or later, which includes proper input validation for ticket number formats. Administrators should implement strict input validation controls that limit the maximum number of digits allowed in ticket format configurations, typically to a reasonable range such as 10-20 digits. Network-level protections can include implementing rate limiting and input filtering mechanisms to prevent malformed requests from reaching the application. Additionally, organizations should conduct thorough vulnerability assessments of their support ticket systems and establish monitoring procedures to detect unusual configuration changes that might indicate exploitation attempts. Regular security updates and proper configuration management practices are essential to prevent similar vulnerabilities from emerging in other components of the ticketing infrastructure.