CVE-2019-9580 in Web UI
Summary
by MITRE
In st2web in StackStorm Web UI before 2.9.3 and 2.10.x before 2.10.3, it is possible to bypass the CORS protection mechanism via a "null" origin value, potentially leading to XSS.
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Analysis
by VulDB Data Team • 07/31/2023
The vulnerability identified as CVE-2019-9580 affects the st2web component within the StackStorm Web UI, specifically targeting versions prior to 2.9.3 and 2.10.x before 2.10.3. This issue represents a critical security flaw that undermines the browser's cross-origin resource sharing protection mechanisms, creating potential pathways for malicious actors to exploit web applications. The vulnerability manifests through improper handling of the "null" origin value in CORS headers, which allows attackers to bypass intended security restrictions.
The technical implementation flaw occurs when the StackStorm Web UI processes HTTP requests containing a "null" origin header value. Under normal circumstances, browsers enforce CORS policies to prevent unauthorized cross-origin requests, but this vulnerability demonstrates how the system fails to properly validate or reject requests originating from a null origin. The null origin value, which typically indicates that the request comes from a file:// protocol or an unknown source, is not being appropriately handled by the CORS validation logic. This oversight creates a condition where malicious web pages or scripts can craft requests that appear to originate from a trusted source, effectively circumventing the security boundaries designed to protect the application.
The operational impact of this vulnerability extends beyond simple bypass of CORS protections, as it creates potential for cross-site scripting attacks that could compromise user sessions and sensitive data. When attackers can bypass CORS restrictions, they gain the ability to inject malicious scripts into the target application's context, potentially accessing user credentials, performing unauthorized actions, or exfiltrating confidential information. The vulnerability affects the web-based interface of StackStorm, which is commonly used for automation orchestration and security operations, making it particularly dangerous in environments where security automation is critical. The attack surface is significant as it allows for potential privilege escalation and lateral movement within automated security workflows.
Mitigation strategies for CVE-2019-9580 require immediate patching of affected StackStorm Web UI components to version 2.9.3 or 2.10.3, respectively, which contain the necessary fixes for CORS validation. Organizations should implement proper input validation for origin headers, ensuring that null origins are either rejected or properly handled according to security best practices. The fix typically involves strengthening the CORS implementation to explicitly reject requests with null origins unless explicitly permitted by administrators. This vulnerability aligns with CWE-346, which addresses "Improper Verification of Source of a Communication Channel," and relates to ATT&CK technique T1059.007 for script injection. Security teams should conduct thorough testing to ensure that the patch does not introduce regressions in legitimate functionality while monitoring for any signs of exploitation attempts in their network traffic logs.