CVE-2019-10264 in Cloud Backup Suite
Summary
by MITRE
An issue was discovered in Ahsay Cloud Backup Suite before 8.1.1.50. With a valid administrator account, the "Move / Import / Export Users" screen has an Import Users option. This option accepts a ZIP archive containing a users.xml file that can trigger XXE.
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Analysis
by VulDB Data Team • 11/13/2023
The vulnerability identified as CVE-2019-10264 represents a critical server-side XML external entity injection flaw within the Ahsay Cloud Backup Suite software. This vulnerability exists in versions prior to 8.1.1.50 and specifically affects the administrative functionality of the system. The flaw is particularly concerning because it allows authenticated administrators to potentially execute arbitrary code or perform unauthorized data access through carefully crafted XML input. The vulnerability stems from insufficient input validation and sanitization within the import mechanism that processes user data files. Attackers with valid administrator credentials can exploit this weakness by uploading a malicious ZIP archive containing a specially crafted users.xml file that triggers XML external entity processing. This type of vulnerability falls under CWE-611, which specifically addresses Improper Restriction of XML External Entity Reference. The attack vector is particularly dangerous because it leverages legitimate administrative functionality to execute malicious code or extract sensitive information from the server environment. The vulnerability enables potential attackers to access internal resources, perform data exfiltration, or escalate privileges within the backup system.
The technical implementation of this vulnerability occurs within the import users functionality of the Ahsay Cloud Backup Suite administrative interface. When an administrator selects the Import Users option and uploads a ZIP archive containing a users.xml file, the system processes the XML content without proper validation of external entity references. The XML parser used by the application fails to properly restrict external entity resolution, allowing attackers to define external entities that can reference local files or network resources. This processing occurs server-side, meaning that the attacker's malicious XML payload can cause the server to read arbitrary files from the local filesystem or make network requests to external servers. The vulnerability is classified as a server-side XXE attack under the ATT&CK framework category T1213.002, which covers Data from Information Repositories. The impact of this vulnerability extends beyond simple data access, as it can potentially allow attackers to read sensitive configuration files, database credentials, or other administrative data stored on the server. The exploitation process requires only a valid administrator account, making it particularly dangerous in environments where administrative privileges are compromised or where credential theft occurs through other means.
The operational impact of CVE-2019-10264 is significant for organizations relying on Ahsay Cloud Backup Suite for their data protection needs. Successful exploitation can lead to unauthorized access to backup data, potential data loss, or complete system compromise. Organizations may experience unauthorized access to sensitive backup files, which could include customer data, financial records, or proprietary information. The vulnerability can also enable attackers to extract administrative credentials or configuration details that could be used for further attacks within the network. Additionally, the attack can potentially cause denial of service conditions if the malicious XML payload causes the system to consume excessive resources or crash during XML parsing. The risk is compounded by the fact that this vulnerability affects the administrative interface, which typically has elevated privileges and access to critical system resources. Organizations may also face regulatory compliance issues if sensitive data is accessed or exfiltrated through this vulnerability, particularly in industries subject to data protection regulations such as healthcare, finance, or government sectors. The vulnerability can also serve as a stepping stone for attackers to move laterally within the network or escalate privileges to gain access to other systems that rely on the same backup infrastructure.
Organizations should implement immediate mitigations to address this vulnerability by upgrading to Ahsay Cloud Backup Suite version 8.1.1.50 or later, which includes proper input validation and XML parsing restrictions. Security teams should also implement network monitoring to detect unusual import activities or attempts to upload suspicious XML files. Additional protective measures include restricting administrative access to only necessary personnel, implementing multi-factor authentication for administrative accounts, and conducting regular security assessments of backup systems. The remediation process should involve disabling unnecessary import functionality where possible and implementing strict file validation for all uploaded content. Organizations should also establish secure coding practices that prevent XML external entity processing in applications handling user input. Security controls should include regular patch management procedures and vulnerability scanning to identify similar weaknesses in other systems. The implementation of web application firewalls can provide additional protection against XXE attacks by filtering malicious XML content before it reaches the application layer. Regular security awareness training for administrators can help prevent social engineering attacks that might lead to credential compromise, which is necessary to exploit this vulnerability. Organizations should also maintain comprehensive backup strategies that include regular testing of restore procedures to ensure that any data corruption or compromise can be effectively addressed. The vulnerability serves as a reminder of the critical importance of validating all external input and implementing proper security controls in administrative interfaces where elevated privileges are available.