CVE-2023-0833: Squareup Okhttp Information Disclosure Flaw

CVE-2023-0833 Overview

A flaw was found in Red Hat's AMQ-Streams, which ships a version of the OKHttp component with an information disclosure flaw via an exception triggered by a header containing an illegal value. This issue could allow an authenticated attacker to access information outside of their regular permissions.

Critical Impact

Authenticated attackers can exploit improper error handling in OKHttp to gain unauthorized access to sensitive information through exception messages triggered by malformed HTTP headers.

Affected Products

• Squareup OKHttp
• Red Hat A-MQ Streams

Discovery Timeline

• 2023-09-27 - CVE CVE-2023-0833 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2023-0833

Vulnerability Analysis

This vulnerability (CWE-209: Generation of Error Message Containing Sensitive Information) occurs in the OKHttp HTTP client library bundled with Red Hat AMQ-Streams. When the library encounters an HTTP header containing an illegal value, it generates an exception that may inadvertently expose sensitive information in the error message. This information disclosure flaw requires local access and low-privilege authentication to exploit, but can result in high-impact exposure of confidential data.

The vulnerability affects the header parsing functionality within OKHttp. When processing HTTP responses or requests, if a header contains characters or values that violate HTTP specifications, the exception handler exposes more information than necessary, potentially revealing internal system details, configuration data, or other sensitive information that should remain protected.

Root Cause

The root cause of CVE-2023-0833 lies in improper error handling within the OKHttp library's header parsing mechanism. When the library encounters headers with illegal values, the exception messages are not properly sanitized before being logged or returned. This violates the principle of least information exposure, where error messages should contain only the minimum information necessary for debugging without revealing sensitive system internals.

Attack Vector

The attack vector for this vulnerability is local, requiring an authenticated attacker with low privileges to trigger the condition. The attacker must be able to craft or influence HTTP requests or responses containing headers with illegal values. When processed by the vulnerable OKHttp component, these malformed headers trigger exceptions that leak sensitive information in the error output.

The exploitation flow involves:

1. An authenticated user with local access to the system
2. Crafting HTTP headers with deliberately malformed or illegal values
3. Sending requests through the OKHttp component in AMQ-Streams
4. Capturing and analyzing the exception messages to extract sensitive information

This vulnerability does not require user interaction and affects confidentiality without impacting integrity or availability. For technical details on the vulnerability mechanism, refer to the GitHub Issue Discussion on OkHttp.

Detection Methods for CVE-2023-0833

Indicators of Compromise

• Unusual exception logs containing HTTP header parsing errors with verbose error messages
• Authentication logs showing repeated requests with malformed headers from specific user accounts
• Application logs revealing internal system paths, configuration details, or stack traces in OKHttp exception output
• Anomalous access patterns where authenticated users retrieve information outside their permission scope

Detection Strategies

• Monitor application logs for OKHttp exceptions related to header parsing with unusually detailed error messages
• Implement log analysis rules to detect patterns of malformed HTTP header attempts
• Review audit logs for authenticated users accessing data beyond their authorized permissions
• Deploy application-level monitoring to flag requests containing non-standard or illegal header values

Monitoring Recommendations

• Configure centralized logging for all AMQ-Streams components to capture OKHttp exceptions
• Establish baseline patterns for normal header parsing behavior and alert on deviations
• Implement real-time alerting for exception messages that contain potential sensitive data patterns
• Regularly audit authenticated user activity for access anomalies that may indicate exploitation attempts

How to Mitigate CVE-2023-0833

Immediate Actions Required

• Apply Red Hat security patches referenced in RHSA-2023:1241 and RHSA-2023:3223
• Update OKHttp library to a patched version in affected AMQ-Streams deployments
• Review and audit authenticated user permissions to ensure least-privilege access
• Enable enhanced logging to detect potential exploitation attempts prior to patching

Patch Information

Red Hat has released security advisories addressing this vulnerability. Organizations should apply the relevant patches based on their deployment:

• Red Hat Security Advisory RHSA-2023:1241 - Initial security fix for AMQ-Streams
• Red Hat Security Advisory RHSA-2023:3223 - Additional security updates

Additional details are available in Red Hat Bug Report #2169845 and the Red Hat CVE-2023-0833 Details page.

Workarounds

• Implement input validation at the network perimeter to filter requests with malformed HTTP headers
• Configure error handling to suppress detailed exception information in production environments
• Restrict local access to AMQ-Streams components to minimize the attack surface
• Apply network segmentation to limit authenticated user access to only necessary services

# Configuration example - Suppress verbose error logging in production
# Add to application configuration to minimize information exposure
# Note: This is a temporary workaround - apply vendor patches when available
export OKHTTP_LOG_LEVEL=NONE
export AMQ_STREAMS_ERROR_VERBOSITY=minimal