CVE-2015-4626 in C2Box
Summary
by MITRE
B.A.S C2Box before 4.0.0 (r19171) relies on client-side validation, which allows remote attackers to "corrupt the business logic" via a negative value in an overdraft.
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Analysis
by VulDB Data Team • 05/14/2026
The vulnerability identified as CVE-2015-4626 affects B.A.S C2Box versions prior to 4.0.0 build 19171 and represents a critical business logic flaw stemming from inadequate server-side validation mechanisms. This issue manifests when the system processes overdraft transactions where client-side validation fails to properly enforce business rules, allowing malicious actors to manipulate transaction parameters through negative values that should be rejected by the system.
The technical flaw resides in the application's reliance on client-side validation for critical business logic controls rather than implementing robust server-side verification mechanisms. When users attempt overdraft transactions, the system accepts negative values that would normally be rejected by proper validation routines, creating a scenario where business logic can be corrupted through manipulation of input parameters. This vulnerability falls under the CWE-693 category of Protection Mechanism Failure, specifically involving inadequate validation of input data that should be strictly controlled by the server-side business logic components.
The operational impact of this vulnerability is significant as it allows remote attackers to exploit the system's weak validation controls to manipulate financial transaction processing. Attackers can potentially bypass overdraft limits, create unauthorized negative balances, or manipulate transaction amounts in ways that could result in financial loss for the organization. The remote nature of the attack means that threat actors do not require physical access to the system or network, making this vulnerability particularly dangerous in environments where the system is exposed to external networks.
From a cybersecurity perspective, this vulnerability aligns with ATT&CK technique T1070.004 which involves the use of system binary proxies to execute malicious code, and more broadly relates to privilege escalation and data manipulation techniques. The flaw demonstrates poor secure coding practices where business logic validation is not properly implemented at the server level, creating opportunities for attackers to exploit the system's trust in client-side controls. Organizations utilizing this software would face potential financial losses, regulatory compliance issues, and reputational damage if this vulnerability were successfully exploited.
The recommended mitigations include implementing comprehensive server-side validation for all transaction parameters, particularly those related to overdraft limits and balance calculations. Organizations should ensure that all business logic validation occurs on the server side with proper input sanitization and parameter checking. Additionally, regular security assessments and code reviews should be conducted to identify similar validation flaws in other system components. The fix should involve upgrading to B.A.S C2Box version 4.0.0 or later, which addresses this specific validation weakness by implementing proper server-side controls for transaction processing and business rule enforcement.