CVE-2021-36802 in Akaunting
Summary
by MITRE • 08/05/2021
Akaunting version 2.1.12 and earlier suffers from a denial-of-service issue that is triggered by setting a malformed 'locale' variable and sending it in an otherwise normal HTTP POST request. This issue was fixed in version 2.1.13 of the product.
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Analysis
by VulDB Data Team • 08/08/2021
The vulnerability identified as CVE-2021-36802 represents a denial-of-service weakness in Akaunting version 2.1.12 and earlier systems that demonstrates a critical flaw in input validation and request handling mechanisms. This issue specifically targets the application's locale parameter processing, where an attacker can craft a malformed locale variable to disrupt normal service operations. The vulnerability manifests when a maliciously constructed locale value is included in an otherwise legitimate HTTP POST request, causing the application to fail in processing the request properly and ultimately leading to a service interruption. The flaw exists within the application's request parsing logic where insufficient validation occurs on the locale parameter before it is processed, allowing arbitrary input to potentially crash or destabilize the system.
The technical implementation of this vulnerability stems from inadequate parameter sanitization within the Akaunting framework's locale handling code. When the application receives a POST request containing a malformed locale variable, the system fails to properly validate or sanitize this input before attempting to process it within the application's localization subsystem. This lack of proper input validation creates an entry point where malicious actors can exploit the system's failure to handle unexpected parameter values gracefully. The vulnerability operates at the application layer and specifically targets the HTTP request processing pipeline where locale parameters are interpreted and utilized by the framework's internationalization components. The flaw can be categorized under CWE-20 as "Improper Input Validation" and aligns with ATT&CK technique T1499.100 for "Network Denial of Service" as it specifically enables an attacker to disrupt service availability through crafted input parameters.
The operational impact of this vulnerability extends beyond simple service disruption, as it can potentially be exploited to exhaust system resources or cause cascading failures within the application's processing pipeline. An attacker can repeatedly send malformed requests containing the malicious locale parameter, leading to sustained denial-of-service conditions that may require system restarts or manual intervention to resolve. The vulnerability affects the entire user base of affected Akaunting installations, as any user who submits a POST request with the malformed locale parameter can trigger the denial-of-service condition. This weakness is particularly concerning because it requires minimal technical expertise to exploit, making it a potentially dangerous vulnerability that can be leveraged by attackers with limited skills to disrupt business operations and service availability. Organizations utilizing vulnerable versions of Akaunting face significant risk of operational disruption and potential financial losses due to service unavailability.
The mitigation strategy for CVE-2021-36802 requires immediate deployment of the patched version 2.1.13, which implements proper input validation and sanitization for locale parameters. System administrators should conduct comprehensive vulnerability assessments to identify all affected installations and ensure that the update is applied across all environments. Additional defensive measures include implementing request rate limiting and input validation at the application firewall level to prevent malformed locale parameters from reaching the application layer. Organizations should also consider implementing monitoring solutions that can detect unusual request patterns or malformed parameters that may indicate exploitation attempts. The fix in version 2.1.13 addresses the root cause by introducing proper parameter validation that rejects malformed locale values before they can trigger the denial-of-service condition, thereby preventing the vulnerability from being exploited. Security teams should also review their incident response procedures to ensure readiness for potential exploitation attempts and establish clear protocols for handling denial-of-service incidents affecting their accounting software infrastructure.