CVE-2018-10922 in ttembed
Summary
by MITRE
An input validation flaw exists in ttembed. With a crafted input file, an attacker may be able to trigger a denial of service condition due to ttembed trusting attacker controlled values.
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Analysis
by VulDB Data Team • 04/29/2023
The vulnerability identified as CVE-2018-10922 represents a critical input validation flaw within the ttembed utility, which is commonly used for embedding fonts in PostScript and PDF documents. This issue stems from the application's failure to properly validate user-supplied input data, creating a pathway for malicious actors to manipulate the software's behavior through crafted file inputs. The vulnerability specifically affects the ttembed component's handling of font embedding operations, where it blindly trusts and processes attacker-controlled values without sufficient sanitization or verification mechanisms. Such a flaw falls under the category of improper input validation as classified by CWE-20, which is a fundamental weakness that enables various attack vectors including denial of service conditions.
The technical exploitation of this vulnerability occurs when an attacker constructs a malicious input file that contains malformed or unexpected data sequences that ttembed processes without proper validation. When the utility encounters these crafted inputs, it fails to properly handle the unexpected values, leading to a denial of service condition where the application becomes unresponsive or crashes entirely. The flaw essentially allows an attacker to inject control flow disruptions through the input processing pipeline, causing the application to enter an unstable state that prevents normal operation. This type of vulnerability is particularly concerning because it can be exploited remotely without requiring authentication, making it accessible to any attacker who can submit input to the affected system. The operational impact extends beyond simple service disruption as it can potentially be leveraged to exhaust system resources or cause cascading failures in applications that depend on ttembed for font processing operations.
The implications of CVE-2018-10922 align with several tactics outlined in the MITRE ATT&CK framework, particularly those related to denial of service and privilege escalation through application-level vulnerabilities. Attackers can utilize this weakness to perform resource exhaustion attacks against systems that rely on ttembed for document processing, potentially affecting web applications, print servers, or document management systems. The vulnerability's classification as a denial of service condition according to CWE-400 indicates that it can be exploited to make services unavailable to legitimate users, which is a significant concern for enterprise environments where document processing is critical. Organizations using affected versions of ttembed should consider this vulnerability as a potential entry point for broader attack campaigns, as the denial of service condition can serve as a precursor to more sophisticated attacks or be used to mask other malicious activities.
Mitigation strategies for CVE-2018-10922 should focus on implementing robust input validation mechanisms and restricting access to the vulnerable ttembed utility. Organizations should immediately upgrade to patched versions of the software that address the input validation flaw, as provided by the software vendor or through official security advisories. Additionally, implementing proper input sanitization and validation checks within the application layer can help prevent malicious input from reaching the vulnerable processing functions. Network segmentation and access controls should be enforced to limit exposure of systems running ttembed to untrusted users or external networks. Regular security assessments and penetration testing should include verification of input validation mechanisms to ensure that similar vulnerabilities do not exist in other components of the system architecture. The vulnerability also highlights the importance of defensive programming practices and adherence to secure coding guidelines that emphasize the principle of least privilege and input validation as fundamental security controls.