CVE-2021-21783: Genivia gSOAP RCE Vulnerability

CVE-2021-21783 Overview

A critical remote code execution vulnerability exists in the WS-Addressing plugin functionality of Genivia gSOAP 2.8.107. This vulnerability allows an attacker to execute arbitrary code on affected systems by sending a specially crafted SOAP request. The attack can be initiated remotely via an HTTP request without requiring any authentication or user interaction, making it particularly dangerous for exposed services.

Critical Impact

Remote code execution through specially crafted SOAP requests can lead to complete system compromise, data exfiltration, and lateral movement within enterprise networks.

Affected Products

• Genivia gSOAP 2.8.107
• Oracle Communications Diameter Signaling Router
• Oracle Communications Eagle Application Processor
• Oracle Communications Eagle LNP Application Processor (versions 46.7, 46.8, 46.9)
• Oracle Communications LSMS (versions 13.1, 13.2, 13.3, 13.4)
• Oracle Tekelec Virtual Operating Environment

Discovery Timeline

• 2021-03-25 - CVE-2021-21783 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2021-21783

Vulnerability Analysis

This vulnerability is classified under CWE-680 (Integer Overflow to Buffer Overflow) and CWE-190 (Integer Overflow or Wraparound). The WS-Addressing plugin in gSOAP fails to properly validate input sizes, which can lead to an integer overflow condition. When processing certain fields in SOAP message headers, the calculation of buffer sizes can wrap around due to integer overflow, resulting in the allocation of an undersized buffer. Subsequent operations that write data to this buffer can overflow it, potentially allowing an attacker to overwrite critical memory structures and achieve code execution.

The vulnerability is particularly severe because it can be triggered remotely through standard HTTP/SOAP communications without requiring any form of authentication. Any service using the vulnerable WS-Addressing plugin and exposed to network traffic is at risk.

Root Cause

The root cause of CVE-2021-21783 lies in improper integer handling within the WS-Addressing plugin's SOAP message parsing logic. When processing WS-Addressing header elements, the plugin performs arithmetic operations on size values derived from user-controlled input without adequate bounds checking. This allows an attacker to supply values that cause integer overflow during buffer size calculations, ultimately leading to heap or stack-based buffer overflows when data is copied into the undersized buffer.

Attack Vector

The attack can be executed remotely over the network by sending a malicious SOAP request to a vulnerable gSOAP service endpoint. The attacker crafts a SOAP message with specially formatted WS-Addressing headers containing values designed to trigger the integer overflow condition. Upon processing this malicious request, the vulnerable service allocates an insufficient buffer and subsequently overflows it, potentially allowing the attacker to corrupt memory and redirect execution flow to attacker-controlled code.

The vulnerability manifests in the WS-Addressing plugin's header processing functionality. When certain size-related values in the SOAP request exceed safe boundaries, integer arithmetic used to calculate buffer sizes wraps around, leading to heap corruption during subsequent memory operations. For detailed technical analysis, see the Talos Intelligence Vulnerability Report.

Detection Methods for CVE-2021-21783

Indicators of Compromise

• Unusual SOAP requests containing abnormally large or malformed WS-Addressing header elements
• Unexpected service crashes or memory corruption errors in gSOAP-based applications
• Anomalous network traffic patterns to SOAP service endpoints with oversized header fields
• Process spawning or unexpected child processes originating from gSOAP services

Detection Strategies

• Deploy network-based intrusion detection rules to identify malformed SOAP requests with suspicious WS-Addressing headers
• Implement application-level logging to capture and analyze all incoming SOAP requests for anomalous patterns
• Monitor gSOAP service processes for signs of memory corruption, crashes, or unexpected behavior
• Use SentinelOne's behavioral AI engine to detect exploitation attempts through memory anomaly detection

Monitoring Recommendations

• Enable detailed logging on all SOAP service endpoints to capture request metadata and header information
• Configure real-time alerting for gSOAP service crashes or abnormal terminations
• Deploy SentinelOne agents on systems running vulnerable gSOAP services for continuous behavioral monitoring
• Establish baseline network traffic patterns for SOAP services to identify deviations indicative of exploitation attempts

How to Mitigate CVE-2021-21783

Immediate Actions Required

• Identify all instances of Genivia gSOAP 2.8.107 and affected Oracle products within your environment
• Apply vendor-provided security patches immediately or implement network-level access controls to restrict access to vulnerable services
• Consider temporarily disabling the WS-Addressing plugin if it is not required for business operations
• Deploy SentinelOne endpoint protection to monitor for exploitation attempts during the patching window

Patch Information

Genivia has released updates to address this vulnerability in gSOAP. Oracle has also addressed this vulnerability in their affected products through their Critical Patch Updates. For Oracle products, refer to the Oracle October 2021 Security Alert and the Oracle January 2022 Security Alert for specific patch information and remediation guidance. Administrators should upgrade to the latest patched versions of gSOAP and apply the relevant Oracle CPU patches to all affected Oracle Communications products.

Workarounds

• Implement network segmentation to isolate gSOAP services from untrusted networks and limit exposure
• Deploy a Web Application Firewall (WAF) with rules to inspect and filter malformed SOAP requests before they reach vulnerable services
• Restrict network access to SOAP service endpoints using firewall rules to allow only authorized clients
• Disable or remove the WS-Addressing plugin if it is not essential for application functionality

# Example: Restrict access to SOAP service port using iptables
iptables -A INPUT -p tcp --dport 8080 -s trusted_network/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 8080 -j DROP