CVE-2021-27612 Overview
CVE-2021-27612 is an open redirect vulnerability (CWE-601) affecting SAP GUI for Windows that allows attackers to redirect users to malicious websites. In specific situations, SAP GUI for Windows forwards users to attacker-controlled websites that could contain malware or be used in phishing attacks to steal victim credentials. This vulnerability requires user interaction but can be exploited remotely over the network.
Critical Impact
Organizations using vulnerable versions of SAP GUI for Windows are at risk of credential theft and malware infection through crafted redirect attacks targeting SAP users.
Affected Products
- SAP GUI for Windows 7.60 (all patch levels through PL9)
- SAP GUI for Windows 7.60 Patch Level 8 Hotfix 1
- SAP GUI for Windows 7.70 PL0
Discovery Timeline
- May 11, 2021 - CVE-2021-27612 published to NVD
- November 21, 2024 - Last updated in NVD database
Technical Details for CVE-2021-27612
Vulnerability Analysis
This open redirect vulnerability (CWE-601) occurs when SAP GUI for Windows fails to properly validate URLs before redirecting users. The application accepts external input that specifies a redirect target without adequately verifying that the destination is a trusted location. This allows attackers to craft malicious links that, when clicked by a victim, redirect them from the trusted SAP GUI context to an attacker-controlled website.
The vulnerability is exploitable over the network and requires user interaction—specifically, the victim must click on a malicious link or interact with crafted content. While the vulnerability does not directly compromise system integrity at a high level, it facilitates secondary attacks including credential harvesting through convincing phishing pages and potential malware delivery.
Root Cause
The root cause of CVE-2021-27612 lies in insufficient URL validation within the SAP GUI for Windows application. The software does not adequately verify or sanitize redirect parameters before forwarding users to external destinations. This allows attackers to manipulate URL parameters to redirect users from a trusted SAP context to arbitrary external websites under attacker control.
Attack Vector
The attack leverages the network-accessible nature of SAP GUI for Windows. An attacker crafts a malicious URL or link that appears to originate from or be associated with a legitimate SAP resource. When a user clicks on this link or interacts with the malicious content, SAP GUI processes the redirect without proper validation and forwards the user to the attacker's website.
This attacker-controlled destination can host:
- Phishing pages mimicking SAP login screens to harvest credentials
- Drive-by download attacks delivering malware payloads
- Social engineering content exploiting user trust in the SAP application
The attack is particularly effective because the initial redirect originates from trusted SAP GUI software, lending legitimacy to the malicious destination in the user's perception.
Detection Methods for CVE-2021-27612
Indicators of Compromise
- Unexpected browser redirects occurring after SAP GUI interactions
- User reports of being directed to unfamiliar websites when using SAP GUI
- Network traffic showing connections to suspicious external domains following SAP GUI activity
- Unusual URL patterns in SAP GUI link handlers containing external domain references
Detection Strategies
- Monitor network traffic for outbound connections to known malicious or suspicious domains originating from SAP GUI processes
- Implement URL filtering and web proxy rules to detect and block redirect attempts to untrusted destinations
- Deploy endpoint detection solutions that monitor SAP GUI application behavior for anomalous redirect patterns
- Review browser history and network logs for unexpected navigation patterns correlating with SAP GUI usage
Monitoring Recommendations
- Enable detailed logging for SAP GUI client activities and URL handling events
- Configure web proxies to log and alert on redirects from SAP-related contexts to external domains
- Monitor for phishing campaigns targeting SAP users that may leverage this vulnerability
- Track user reports of suspicious redirects as potential indicators of exploitation attempts
How to Mitigate CVE-2021-27612
Immediate Actions Required
- Update SAP GUI for Windows to the latest patched version beyond 7.60 PL9 and 7.70 PL0
- Apply SAP Security Note #3023078 immediately to all affected installations
- Educate users about the risks of clicking untrusted links, even when they appear to originate from SAP contexts
- Implement network-level URL filtering to block known malicious redirect destinations
Patch Information
SAP has released a security patch addressing this vulnerability. Organizations should apply SAP Security Note #3023078 to remediate this issue. Additional information is available in the SAP Wiki Security Overview.
Workarounds
- Implement strict web filtering policies that block redirects to untrusted external domains from SAP GUI processes
- Deploy endpoint protection that monitors and restricts SAP GUI network communications
- Train users to verify destination URLs before entering credentials after any redirect
- Consider network segmentation to limit SAP GUI client internet access to known-safe destinations
# Example: Web proxy rule to log SAP GUI redirects (conceptual)
# Configure your organization's web proxy or firewall to log
# outbound requests from SAP GUI processes to external domains
# and alert on redirects to non-whitelisted destinations
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
