CVE-2019-17555 in Olingo
Summary
by MITRE
The AsyncResponseWrapperImpl class in Apache Olingo versions 4.0.0 to 4.6.0 reads the Retry-After header and passes it to the Thread.sleep() method without any check. If a malicious server returns a huge value in the header, then it can help to implement a DoS attack.
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Analysis
by VulDB Data Team • 12/05/2019
The vulnerability identified as CVE-2019-17555 resides within the AsyncResponseWrapperImpl class of Apache Olingo, a popular open-source library for implementing odata services. This flaw affects versions ranging from 4.0.0 through 4.6.0, representing a significant attack surface for malicious actors seeking to exploit denial-of-service conditions. The vulnerability stems from inadequate input validation within the asynchronous response handling mechanism, specifically when processing HTTP Retry-After headers that are intended to indicate how long a client should wait before retrying a request.
The technical implementation of this vulnerability occurs when the AsyncResponseWrapperImpl class processes a Retry-After header value and directly passes it to the Thread.sleep() method without performing any validation or sanitization checks. This design flaw allows attackers to craft malicious responses containing extraordinarily large numeric values in the Retry-After header field, which are then interpreted as milliseconds for thread suspension. When the client application encounters such oversized values, the Thread.sleep() method becomes suspended for an extended period, effectively causing the application to hang or become unresponsive for the duration specified by the malicious header value.
From an operational impact perspective, this vulnerability represents a serious security concern as it enables remote attackers to perform denial-of-service attacks against applications that utilize Apache Olingo for processing asynchronous responses. The attack vector is particularly dangerous because it can be executed through legitimate HTTP responses from malicious servers, requiring no special privileges or complex exploitation techniques. The potential for prolonged service disruption increases significantly when considering that the malicious header values can be set to extremely large numbers, potentially causing indefinite suspension of application threads and rendering the affected systems unavailable to legitimate users.
The vulnerability aligns with CWE-1321, which addresses the improper handling of resource identifiers in a way that can lead to denial-of-service conditions. Additionally, this weakness maps to ATT&CK technique T1499.004, specifically targeting the exploitation of resource consumption vulnerabilities through malicious response manipulation. Organizations utilizing Apache Olingo in their applications face a heightened risk of service disruption, particularly in environments where asynchronous processing is critical for maintaining application availability. The vulnerability demonstrates a clear lack of input validation and resource management best practices, highlighting the importance of implementing proper bounds checking and error handling in network communication libraries.
Mitigation strategies for CVE-2019-17555 should prioritize immediate patching of affected Apache Olingo versions to the latest releases that contain the necessary fixes. Organizations should also implement network-level controls to monitor and restrict potentially malicious Retry-After header values, establishing maximum thresholds for acceptable sleep durations. Application developers should consider implementing custom validation layers that sanitize header values before they are processed by the underlying Olingo library, ensuring that any values passed to Thread.sleep() remain within reasonable bounds. Additionally, system administrators should configure monitoring solutions to detect unusual patterns in response handling that might indicate exploitation attempts, enabling rapid incident response capabilities to minimize potential impact on service availability and user experience.