CVE-2020-4337 in API Connect
Summary
by MITRE
IBM API Connect 2018.4.1.0 through 2018.4.1.12 could allow an attacker to launch phishing attacks by tricking the server to generate user registration emails that contain malicious URLs. IBM X-Force ID: 177933.
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Analysis
by VulDB Data Team • 11/12/2020
The vulnerability identified as CVE-2020-4337 affects IBM API Connect versions 2018.4.1.0 through 2018.4.1.12, representing a critical security flaw that enables man-in-the-middle attack scenarios. This issue stems from improper validation of user registration URLs within the system's email generation mechanism, creating an avenue for attackers to manipulate the content of registration emails sent to users. The vulnerability specifically impacts the authentication and user management components of the API gateway platform, which serves as a central hub for API provisioning and security orchestration in enterprise environments.
The technical flaw manifests when the system processes user registration requests and generates corresponding email notifications containing registration URLs. Attackers can exploit this weakness by crafting malicious input that gets reflected in the generated URLs, potentially redirecting users to phishing sites or malicious domains. This vulnerability falls under CWE-79, which describes cross-site scripting flaws, and more specifically aligns with CWE-601, URL redirection or forward attacks, as it enables unauthorized redirection through email content manipulation. The flaw exists in the server-side email template processing logic where user-supplied data is not adequately sanitized before being incorporated into the URL construction process.
The operational impact of this vulnerability extends beyond simple phishing attacks, as it can enable sophisticated social engineering campaigns targeting enterprise users who trust the legitimate API Connect platform. Organizations using affected versions face significant risks including credential theft, data exfiltration, and potential compromise of the entire API ecosystem. The attack vector leverages the trust relationship between users and the API platform, making it particularly dangerous as users are more likely to click on links that appear to originate from legitimate sources. This vulnerability can be exploited by attackers with minimal privileges, making it accessible to a wide range of threat actors from script kiddies to organized cybercriminals.
Mitigation strategies should focus on immediate patching of affected IBM API Connect versions to 2018.4.1.13 or later, which contain the necessary fixes for URL validation and sanitization. Organizations should also implement additional email security controls including content filtering, URL reputation checks, and email authentication mechanisms such as dkim and spf to detect and block malicious emails. Network-level protections such as web application firewalls and outbound traffic filtering can provide additional layers of defense against exploitation attempts. The vulnerability aligns with attack techniques documented in the mitre ATT&CK framework under T1566, Phishing, and T1190, Exploit Public-Facing Application, highlighting the need for comprehensive defensive measures. Regular security assessments of API gateway configurations and user registration workflows should be conducted to identify similar vulnerabilities in other components of the enterprise API infrastructure.