CVE-2023-54402 in iDocView
Summary
by MITRE • 10/01/2026
iDocView contains a server-side request forgery vulnerability in its /doc/upload endpoint that allows remote unauthenticated attackers to fetch arbitrary URLs by supplying a hardcoded default token value (testtoken) to bypass authentication. Attackers can exploit the unrestricted URL scheme handling, including file:// URIs, to read arbitrary local files such as operating-system and application configuration files, and to reach internal network hosts and services not otherwise accessible. Exploitation evidence was first observed by the Shadowserver Foundation on 2024-03-26.
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Analysis
by VulDB Data Team • 10/01/2026
The vulnerability in iDocView represents a critical server-side request forgery flaw located within the /doc/upload endpoint, which fundamentally undermines the application's security model through inadequate authentication and input validation mechanisms. The core technical issue stems from the use of a hardcoded default token value, specifically testtoken, to bypass access controls. This design oversight allows remote unauthenticated attackers to interact with sensitive endpoints without providing valid credentials or session tokens. By supplying this static string during request transmission, an attacker can successfully authenticate as a legitimate user, thereby gaining unauthorized access to functionality that should be restricted. This type of authentication bypass is particularly dangerous because it requires no prior knowledge of the system's dynamic token generation logic, relying instead on poor development practices where default or test credentials are left in production code.
Beyond simple authentication evasion, the vulnerability extends into a severe server-side request forgery scenario due to unrestricted URL scheme handling within the application backend. Once authenticated via the hardcoded token, attackers can manipulate the target URLs processed by the upload functionality. The system fails to validate or restrict the protocol schemes used in these requests, permitting not only standard HTTP and HTTPS protocols but also dangerous local file access protocols such as file://. This lack of sanitization enables remote code execution equivalents through data exfiltration rather than direct shell access. Attackers can construct malicious payloads that instruct the server to fetch resources from arbitrary locations on its own filesystem or internal network infrastructure, effectively turning the vulnerable application into a proxy for accessing restricted environments.
The operational impact of this vulnerability is profound, allowing attackers to read sensitive local files including operating system configurations and application-specific settings. This capability facilitates deep reconnaissance and credential harvesting, as configuration files often contain database connection strings, API keys, or other secrets necessary for further exploitation. Furthermore, the ability to reach internal network hosts and services expands the attack surface significantly. Attackers can use iDocView as a pivot point to scan and interact with backend databases, internal APIs, or management interfaces that are not exposed to the public internet. This lateral movement capability transforms a single web application vulnerability into a gateway for compromising an entire enterprise network segment, leading to potential data breaches, service disruption, and complete loss of confidentiality and integrity for stored information.
This specific exploitation pattern aligns with several established industry standards and frameworks. The authentication bypass via hardcoded credentials corresponds to CWE-798: Use of Hard-coded Credentials, while the unrestricted URL scheme handling is a classic example of CWE-918: Server-Side Request Forgery (SSRF). Additionally, the ability to read local files maps directly to CWE-200: Exposure of Sensitive Information to an Unauthorized Actor. From a tactical perspective, this vulnerability supports ATT&CK techniques such as T1534: Internal Spearphishing if used for lateral movement, or more accurately T1071: Application Layer Protocol for command and control communication patterns when leveraging the SSRF capabilities. The initial exploitation evidence observed by the Shadowserver Foundation on March 26, 2024, indicates active real-world targeting of this flaw in production environments.
Mitigation strategies must address both the authentication weakness and the input validation failures immediately. Developers should remove all hardcoded default tokens from production code and implement robust session management with unique, unpredictable token generation for each user session. Access control checks on the /doc/upload endpoint must be enforced server-side without relying solely on client-supplied parameters that can be easily spoofed. To prevent SSRF, input validation mechanisms must strictly whitelist allowed URL schemes, permitting only http and https while explicitly blocking file://, ftp://, gopher://, and other potentially dangerous protocols. Additionally implementing network-level controls such as firewall rules to restrict the application server's outbound traffic to known internal services can limit the blast radius of any successful SSRF attempt. Regular security audits and static code analysis tools configured to detect hardcoded secrets are essential for preventing similar vulnerabilities in future releases.