CVE-2021-33673 in Contact Center
Summary
by MITRE • 09/14/2021
Under certain conditions, SAP Contact Center - version 700,does not sufficiently encode user-controlled inputs and persists in them. This allows an attacker to exploit a Stored Cross-Site Scripting (XSS) vulnerability when a user browses through the employee directory and to execute arbitrary code on the victim's browser. Due to the usage of ActiveX in the application, the attacker can further execute operating system level commands.
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Analysis
by VulDB Data Team • 09/17/2021
The vulnerability identified as CVE-2021-33673 affects SAP Contact Center version 700 and represents a critical stored cross-site scripting flaw that enables remote code execution through browser-based attacks. This vulnerability stems from insufficient input validation and encoding mechanisms within the application's employee directory functionality, where user-controlled data is persistently stored without adequate sanitization. The flaw allows attackers to inject malicious scripts that execute when other users browse the directory, creating a persistent threat vector that can compromise multiple victims within the organization.
The technical implementation of this vulnerability involves the application's failure to properly encode user inputs before storing them in the database or application memory. When users interact with the employee directory, the system processes and displays user-supplied information without sufficient sanitization, creating an environment where malicious scripts can be stored and later executed. This stored XSS condition is particularly dangerous because the malicious code persists across user sessions and can affect any individual who accesses the vulnerable directory functionality. The vulnerability's severity is amplified by the application's use of ActiveX components, which provide additional attack surface for executing operating system level commands.
The operational impact of CVE-2021-33673 extends beyond simple script execution, as the ActiveX integration allows attackers to escalate privileges and execute arbitrary commands on the victim's operating system. This creates a complete compromise scenario where attackers can potentially gain full system access, access sensitive data, install malware, or establish persistent backdoors within the organization's infrastructure. The vulnerability affects the application's authentication and authorization mechanisms, as compromised user sessions can be leveraged to access restricted functionality and data within the SAP Contact Center environment.
Security professionals should recognize this vulnerability as a direct violation of CWE-79, which addresses cross-site scripting flaws in web applications. The vulnerability also maps to ATT&CK technique T1566, specifically the use of spearphishing with malicious attachments, as attackers can exploit this flaw to deliver malicious payloads through seemingly legitimate directory browsing activities. Organizations should implement immediate mitigations including input validation and output encoding controls, regular security assessments, and monitoring for suspicious directory access patterns. The vulnerability demonstrates the critical importance of proper input sanitization and the dangers of combining legacy ActiveX technologies with modern web applications without adequate security controls, highlighting the need for comprehensive security testing throughout the application lifecycle.