CVE-2020-11987: Apache Batik SSRF Vulnerability

CVE-2020-11987 Overview

Apache Batik 1.13 is vulnerable to Server-Side Request Forgery (SSRF), caused by improper input validation in the NodePickerPanel component. By using a specially-crafted argument, an attacker could exploit this vulnerability to cause the underlying server to make arbitrary GET requests. This vulnerability enables attackers to interact with internal services, potentially exposing sensitive data or enabling further exploitation of internal network resources.

Critical Impact

Attackers can leverage this SSRF vulnerability to make unauthorized GET requests from the vulnerable server, potentially accessing internal services, cloud metadata endpoints, or other restricted resources that should not be accessible from the public internet.

Affected Products

• Apache Batik (versions prior to patched release)
• Oracle WebLogic Server (versions 12.2.1.3.0, 12.2.1.4.0, 14.1.1.0.0)
• Oracle Banking APIs and Digital Experience (versions 18.3, 19.1, 19.2, 20.1, 21.1)
• Oracle Communications products including MetaSolv Solution and Offline Mediation Controller
• Oracle Retail products including Back Office, Central Office, and Point-of-Service (version 14.1)
• Oracle FLEXCUBE Universal Banking
• Fedora 33 and 34
• Debian Linux 10.0

Discovery Timeline

• 2021-02-24 - CVE-2020-11987 published to NVD
• 2025-11-03 - Last updated in NVD database

Technical Details for CVE-2020-11987

Vulnerability Analysis

This Server-Side Request Forgery vulnerability exists within Apache Batik's NodePickerPanel component. Apache Batik is a Java-based toolkit for applications that want to use images in the Scalable Vector Graphics (SVG) format. The vulnerability stems from insufficient input validation when processing user-controlled data that influences outbound HTTP requests.

When exploited, the vulnerability allows an attacker to craft malicious input that causes the server to initiate arbitrary GET requests to attacker-specified destinations. This can lead to unauthorized access to internal network resources, information disclosure from internal services, or interaction with cloud provider metadata services.

The attack can be conducted remotely over the network without requiring authentication or user interaction, making it particularly dangerous for internet-facing applications that incorporate the vulnerable Apache Batik library.

Root Cause

The root cause is classified under CWE-20 (Improper Input Validation). The NodePickerPanel component fails to properly validate and sanitize input before using it to construct HTTP requests. This allows attacker-controlled data to influence the destination URLs of server-initiated requests.

Specifically, the component does not implement adequate restrictions on:

• The protocol schemes that can be used (http, https, file, etc.)
• The destination hosts that can be accessed
• Internal/private IP address ranges that should be blocked

Attack Vector

The attack vector is network-based, allowing remote exploitation. An attacker can exploit this vulnerability by:

1. Identifying an application that uses Apache Batik to process SVG content or related graphical data
2. Crafting a malicious payload containing specially-crafted arguments targeting the NodePickerPanel
3. Submitting the payload to trigger the SSRF vulnerability
4. The vulnerable server then makes arbitrary GET requests on behalf of the attacker

Typical attack scenarios include:

• Accessing cloud metadata services (e.g., AWS 169.254.169.254)
• Scanning internal network services
• Accessing internal APIs and administrative interfaces
• Exfiltrating sensitive data from internal systems

The vulnerability allows high confidentiality impact through potential access to sensitive internal data, with low integrity impact as attackers can manipulate request destinations.

Detection Methods for CVE-2020-11987

Indicators of Compromise

• Unusual outbound HTTP GET requests from servers running Apache Batik to internal IP ranges or cloud metadata endpoints
• Server logs showing requests to 169.254.169.254 (AWS metadata service) or equivalent cloud provider metadata URLs
• Network traffic to internal services that should not be accessed by the application server
• Error logs indicating failed connections to internal hosts from the Batik processing components

Detection Strategies

• Monitor network traffic for outbound requests from application servers to internal RFC 1918 addresses (10.x.x.x, 172.16.x.x-172.31.x.x, 192.168.x.x)
• Implement application-layer firewalls to detect and block SSRF patterns in SVG-related requests
• Deploy web application firewalls (WAF) with rules to detect common SSRF payloads targeting metadata endpoints
• Audit application logs for NodePickerPanel-related processing errors or unexpected URL resolution attempts

Monitoring Recommendations

• Enable detailed logging for all applications utilizing Apache Batik libraries to capture request patterns
• Set up alerts for outbound connections from web/application servers to internal networks or localhost addresses
• Monitor DNS queries for internal hostnames originating from public-facing application servers
• Implement egress filtering and monitoring at the network level to detect unauthorized outbound connections

How to Mitigate CVE-2020-11987

Immediate Actions Required

• Upgrade Apache Batik to the latest patched version immediately
• Inventory all applications using Apache Batik, including those bundled within Oracle products
• Apply Oracle Critical Patch Updates as released in April 2021, July 2021, October 2021, January 2022, and July 2022
• Implement network segmentation to limit the impact of SSRF vulnerabilities
• Block outbound connections from application servers to internal metadata services

Patch Information

Patches are available through multiple channels depending on your affected products:

• Apache Batik: Upgrade to a patched version as documented in the Apache XMLGraphics Security Report
• Oracle Products: Apply the relevant Critical Patch Update. See the Oracle CPU April 2021 Alert, Oracle CPU July 2021 Alert, Oracle CPU October 2021 Alert, Oracle CPU January 2022 Alert, and Oracle CPU July 2022 Alert
• Fedora: Apply updates via the standard package manager as announced in Fedora Package Announcements
• Debian: Apply updates as documented in the Debian LTS Announcements
• Gentoo: See Gentoo GLSA 202401-11 for package updates

Workarounds

• Implement strict egress filtering to prevent application servers from making outbound connections to internal networks and cloud metadata services
• Configure application-level URL allowlists that restrict Batik to only access approved external resources
• Deploy a proxy server for all outbound requests that validates and filters destination URLs before forwarding
• If the NodePickerPanel functionality is not required, consider disabling or removing it from the application configuration
• Implement network-level controls to block access to sensitive internal endpoints from application servers

# Example iptables rules to block SSRF to common metadata endpoints
# Block access to AWS metadata service
iptables -A OUTPUT -d 169.254.169.254 -j DROP

# Block access to internal RFC 1918 ranges from application servers
iptables -A OUTPUT -d 10.0.0.0/8 -j DROP
iptables -A OUTPUT -d 172.16.0.0/12 -j DROP
iptables -A OUTPUT -d 192.168.0.0/16 -j DROP

# Save rules
iptables-save > /etc/iptables/rules.v4