KDE messagelib before 25.11.90 ignores SSL errors for threatMatches:find in the Google Safe Browsing Lookup API (aka phishing API), which might allow spoofing of threat data. NOTE: this Lookup API is not contacted in the messagelib default configuration.
KDE messagelib versions prior to 25.11.90 are vulnerable to a spoofing attack due to improper handling of SSL errors when querying the Google Safe Browsing Lookup API. This allows attackers to potentially bypass security checks and deliver malicious content by manipulating threat data, even though the default configuration does not use this API. This could lead to users being exposed to phishing attacks and other forms of online threats.
Step 1: Configuration: A developer enables the Google Safe Browsing Lookup API within their KDE application using messagelib.
Step 2: Request Interception: An attacker intercepts the network traffic between the KDE application and the Google Safe Browsing Lookup API.
Step 3: SSL/TLS Manipulation: The attacker establishes a Man-in-the-Middle (MITM) position, potentially using a self-signed certificate or a compromised certificate authority.
Step 4: SSL Error Injection: The attacker's MITM proxy deliberately introduces SSL errors during the API communication, such as presenting an invalid certificate or terminating the TLS handshake prematurely.
Step 5: Error Ignorance: messagelib, due to the vulnerability, ignores these SSL errors.
Step 6: Data Spoofing: The attacker provides a crafted response to the KDE application, spoofing the threat data. This response could indicate a safe website is malicious or vice-versa.
Step 7: User Exposure: The KDE application, trusting the spoofed data, allows the user to access the malicious website or displays incorrect security warnings.
The vulnerability stems from a failure in KDE messagelib to properly validate SSL certificates when interacting with the Google Safe Browsing Lookup API, specifically within the threatMatches:find function. The code ignores SSL errors, allowing an attacker to intercept and manipulate the API responses. This is a logic flaw where the expected security checks are bypassed. The root cause is likely a missing or insufficient error handling mechanism for SSL certificate validation, leading to a trust-on-first-use or a similar insecure behavior. The API is not contacted in the default configuration, but if a developer enables it, the vulnerability is present.