CVE-2020-13482 in EM-HTTP-Request
Summary
by MITRE
EM-HTTP-Request 1.1.5 uses the library eventmachine in an insecure way that allows an attacker to perform a man-in-the-middle attack against users of the library. The hostname in a TLS server certificate is not verified.
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Analysis
by VulDB Data Team • 05/26/2020
The vulnerability identified as CVE-2020-13482 affects the EM-HTTP-Request library version 1.1.5 which relies on the EventMachine library for asynchronous HTTP operations. This security flaw creates a critical weakness in the TLS certificate validation process that can be exploited by malicious actors to execute man-in-the-middle attacks against unsuspecting users of the affected library. The root cause lies in the improper implementation of SSL/TLS certificate verification within the EventMachine framework, which fails to validate the hostname present in the server certificate against the expected target host.
This vulnerability represents a classic example of insufficient certificate validation as classified under CWE-295, which specifically addresses the failure to validate certificates in secure communications. The flaw allows attackers to intercept and modify traffic between clients and servers by presenting fraudulent certificates that appear legitimate to the vulnerable library. When the EventMachine library processes HTTP requests, it accepts any valid certificate without properly verifying that the certificate's hostname matches the actual server being contacted, creating an attack surface where cryptographic protections can be bypassed.
The operational impact of this vulnerability extends beyond simple data interception, as it undermines the fundamental security guarantees that TLS encryption provides. Attackers can leverage this weakness to perform session hijacking, data tampering, and credential theft against applications that utilize the affected library. The vulnerability affects any application that depends on EM-HTTP-Request 1.1.5 and EventMachine for secure HTTP communications, potentially compromising sensitive information including authentication tokens, personal data, and business-critical communications. This weakness aligns with ATT&CK technique T1573.001 which describes the use of unencrypted communications and T1566.001 which covers credential access through man-in-the-middle attacks.
Organizations utilizing the affected library should immediately implement mitigations including upgrading to patched versions of both EM-HTTP-Request and EventMachine, implementing additional certificate validation layers, and monitoring for suspicious network activity. The recommended approach involves verifying that all TLS connections properly validate hostname matching and certificate authorities, with particular attention to ensuring that cryptographic libraries perform complete certificate chain validation. Security teams should also consider implementing network-based detection measures to identify potential exploitation attempts and establish proper certificate monitoring procedures to detect unauthorized certificate deployments. This vulnerability highlights the critical importance of proper cryptographic implementation and serves as a reminder that even well-established libraries can contain critical security flaws when certificate validation is not properly enforced.