CVE-2024-3572 in scrapy
Summary
by MITRE • 04/16/2024
The scrapy/scrapy project is vulnerable to XML External Entity (XXE) attacks due to the use of lxml.etree.fromstring for parsing untrusted XML data without proper validation. This vulnerability allows attackers to perform denial of service attacks, access local files, generate network connections, or circumvent firewalls by submitting specially crafted XML data.
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Analysis
by VulDB Data Team • 07/28/2025
The vulnerability identified as CVE-2024-3572 affects the scrapy/scrapy web crawling framework, representing a critical security flaw that stems from improper XML parsing practices within the application. This issue specifically manifests when the lxml.etree.fromstring function processes untrusted XML input without adequate security controls, creating an exploitable condition that violates fundamental principles of secure coding and data validation. The vulnerability falls under the well-documented category of XML External Entity processing, which has been classified as CWE-611 by the Common Weakness Enumeration catalog, indicating a significant risk to system integrity and availability.
The technical implementation of this flaw occurs within the scrapy framework's XML parsing mechanisms where developers rely on lxml.etree.fromstring as the primary method for processing XML content received from external sources. This function, while powerful for legitimate XML processing tasks, lacks proper security configurations that would prevent the evaluation of external entities during parsing operations. Attackers can exploit this by crafting malicious XML payloads that contain external entity declarations, which when processed by the vulnerable scrapy application, can trigger unintended system behaviors. The vulnerability operates at the parser level where XML entities are resolved, bypassing normal security boundaries that should prevent access to local resources or network connections.
The operational impact of CVE-2024-3572 extends beyond simple denial of service conditions to encompass serious data exposure and network compromise scenarios. An attacker can leverage this vulnerability to access local files on the server hosting the scrapy application, potentially obtaining sensitive configuration data, user credentials, or other confidential information stored within the system's file structure. Additionally, the vulnerability enables attackers to establish outbound network connections from the affected system, which could facilitate further attacks or data exfiltration operations. The threat landscape for this vulnerability aligns with ATT&CK technique T1071.004 for application layer protocol usage, specifically targeting XML processing to achieve privilege escalation or lateral movement within compromised environments.
Mitigation strategies for CVE-2024-3572 must address both immediate patching requirements and long-term architectural improvements to prevent similar issues in the future. The primary remediation involves updating to a version of scrapy that properly configures lxml parsers to disable external entity resolution andDTD processing, typically through the use of proper parser configuration flags such as disable_entities=True and disable_external=True. Organizations should also implement input validation measures that sanitize XML content before processing, including schema validation and regular expression filtering to prevent malicious payload injection. The implementation of these security controls aligns with security best practices outlined in the OWASP Top Ten and follows the principle of least privilege by ensuring that XML parsers operate with minimal necessary permissions and access rights. Additionally, network segmentation and monitoring solutions should be deployed to detect anomalous network connections that may indicate exploitation attempts, while regular security assessments should verify that no other similar vulnerabilities exist within the application's codebase or dependencies.