CVE-2013-7397 in Async Http Client
Summary
by MITRE
Async Http Client (aka AHC or async-http-client) before 1.9.0 skips X.509 certificate verification unless both a keyStore location and a trustStore location are explicitly set, which allows man-in-the-middle attackers to spoof HTTPS servers by presenting an arbitrary certificate during use of a typical AHC configuration, as demonstrated by a configuration that does not send client certificates.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 05/21/2022
The vulnerability described in CVE-2013-7397 affects the Async Http Client library, a widely used asynchronous HTTP client implementation in Java applications. This flaw represents a critical security issue that undermines the fundamental purpose of SSL/TLS encryption in secure communications. The vulnerability specifically impacts versions of the library prior to 1.9.0, where the default configuration behavior creates a dangerous security gap that can be exploited by malicious actors.
The technical flaw lies in the certificate verification logic of the Async Http Client library. When users configure the client without explicitly specifying both a keyStore and trustStore location, the library defaults to skipping X.509 certificate verification entirely. This behavior occurs because the library's implementation does not properly validate whether certificate validation should be enabled when only partial SSL/TLS configuration parameters are provided. The vulnerability creates a scenario where the client will accept any certificate presented by a server, regardless of its authenticity or trustworthiness, as long as the typical configuration pattern is used without explicit certificate store definitions.
This security weakness enables man-in-the-middle attacks where attackers can successfully impersonate legitimate HTTPS servers by presenting arbitrary certificates to unsuspecting clients. The attack vector is particularly dangerous because it exploits the common configuration pattern used by developers who rely on default settings rather than explicitly configuring SSL/TLS parameters. When a client connects to a server using a typical AHC configuration that does not send client certificates, the vulnerability becomes exploitable, allowing attackers to intercept and potentially modify communications between the client and server.
The operational impact of this vulnerability extends beyond simple data interception, as it fundamentally compromises the integrity and confidentiality of communications that rely on SSL/TLS encryption. Applications using vulnerable versions of Async Http Client may unknowingly transmit sensitive information to malicious servers without any certificate validation, potentially exposing user credentials, personal data, or business-critical information. The vulnerability affects any application that depends on the Async Http Client library for HTTPS communications, making it a widespread concern across numerous software systems and services.
Organizations should immediately upgrade to Async Http Client version 1.9.0 or later to remediate this vulnerability. The fix implemented in version 1.9.0 ensures that certificate verification is properly enforced even when keyStore and trustStore locations are not explicitly configured. Security teams should also conduct comprehensive audits of their applications to identify all instances where the vulnerable library is used, particularly in environments handling sensitive data. Additionally, developers should review their SSL/TLS configuration practices to ensure that certificate validation is always enabled and properly configured, following industry best practices for secure communications.
This vulnerability maps to CWE-295, which addresses "Improper Certificate Validation," and aligns with ATT&CK technique T1573.002 for "Tunneling through Secure Shell (SSH)" and T1041 for "Exfiltration Over C2 Channel," as attackers can leverage this weakness to establish unauthorized secure communication channels. The vulnerability demonstrates the critical importance of proper SSL/TLS implementation and the dangers of relying on insecure default behaviors in cryptographic libraries, highlighting the need for robust security practices in network communication implementations.