CVE-2020-26820 – This vulnerability allows authenticated adminis... (How to Fix)

Q: What is the severity of CVE-2020-26820?

CVE-2020-26820 has a CVSS score of 7.2 (HIGH). This vulnerability allows authenticated administrators in SAP NetWeaver AS JAVA to upload malicious files that enable remote code execution. Attackers can escalate privileges to compromise the entire server operating system and applications. Affects SAP NetWeaver AS JAVA versions 7.20 through 7.50.

📋 TL;DR

This vulnerability allows authenticated administrators in SAP NetWeaver AS JAVA to upload malicious files that enable remote code execution. Attackers can escalate privileges to compromise the entire server operating system and applications. Affects SAP NetWeaver AS JAVA versions 7.20 through 7.50.

💻 Affected Systems

Products:

SAP NetWeaver AS JAVA

Versions: 7.20, 7.30, 7.31, 7.40, 7.50

Operating Systems: All platforms running SAP NetWeaver AS JAVA

Default Config Vulnerable: ⚠️ Yes

Notes: Requires administrator authentication to exploit initially, but leads to unauthenticated RCE through uploaded files.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete compromise of server operating system with full administrative control, allowing data theft, system destruction, and lateral movement.

🟠

Likely Case

Privilege escalation leading to unauthorized access to sensitive data, application manipulation, and persistence on the system.

🟢

If Mitigated

Limited impact if proper access controls and monitoring prevent unauthorized administrator access and file uploads.

🌐 Internet-Facing: HIGH - If exposed to internet, attackers can exploit after obtaining admin credentials through other means.

🏢 Internal Only: HIGH - Internal attackers with admin access or compromised admin accounts can fully compromise systems.

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: CONFIRMED

Unauthenticated Exploit: ✅ No

Complexity: LOW

Exploit requires admin credentials but then provides straightforward file upload and RCE capabilities. Multiple public exploit references exist.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Apply SAP Security Note 2979062

Vendor Advisory: https://launchpad.support.sap.com/#/notes/2979062

Restart Required: Yes

Instructions:

1. Download and apply SAP Security Note 2979062. 2. Restart SAP NetWeaver AS JAVA services. 3. Verify patch application through transaction SNOTE.

🔧 Temporary Workarounds

Restrict Administrator Console Access

all

Limit access to SAP administrator console to only trusted administrators and implement strict access controls.

File Upload Restrictions

all

Implement file upload restrictions and validation in SAP NetWeaver configuration.

🧯 If You Can't Patch

Implement strict network segmentation to isolate SAP systems from critical infrastructure
Enhance monitoring for unusual file uploads and administrator console access patterns

🔍 How to Verify

Check if Vulnerable:

Check SAP NetWeaver version via transaction SM51 or system info. If version is 7.20-7.50 and SAP Note 2979062 is not applied, system is vulnerable.

Check Version:

Transaction SM51 or check SAP system properties

Verify Fix Applied:

Verify SAP Note 2979062 is applied using transaction SNOTE and check version information.

📡 Detection & Monitoring

Log Indicators:

Unusual file uploads via administrator console
Multiple failed authentication attempts followed by successful admin login
Execution of OS commands from SAP processes

Network Indicators:

Unusual outbound connections from SAP servers
Traffic patterns indicating file transfers from SAP systems

SIEM Query:

source="sap_logs" AND (event="file_upload" OR event="admin_console_access") AND user="administrator"

📊 Metadata

CVE ID: CVE-2020-26820

CVSS v3 Score: 7.2 (HIGH)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-434

Published: November 10, 2020

Last Updated: November 21, 2024

🔗 References

http://packetstormsecurity.com/files/162086/SAP-Java-OS-Remote-Code-Execution.html Third Party Advisory,VDB Entry
http://seclists.org/fulldisclosure/2021/Apr/7 Mailing List,Third Party Advisory
https://launchpad.support.sap.com/#/notes/2979062 Permissions Required,Vendor Advisory
https://wiki.scn.sap.com/wiki/pages/viewpage.action?pageId=562725571 Vendor Advisory
http://packetstormsecurity.com/files/162086/SAP-Java-OS-Remote-Code-Execution.html Third Party Advisory,VDB Entry
http://seclists.org/fulldisclosure/2021/Apr/7 Mailing List,Third Party Advisory
https://launchpad.support.sap.com/#/notes/2979062 Permissions Required,Vendor Advisory
https://wiki.scn.sap.com/wiki/pages/viewpage.action?pageId=562725571 Vendor Advisory

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🔗 Related Vulnerabilities

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📋 TL;DR

💻 Affected Systems

📦 What is this software?

Netweaver Application Server Java by Sap

Netweaver Application Server Java by Sap

Netweaver Application Server Java by Sap

Netweaver Application Server Java by Sap

Netweaver Application Server Java by Sap

⚠️ Risk & Real-World Impact

Worst Case

Likely Case

If Mitigated

🎯 Exploit Status

🛠️ Fix & Mitigation

✅ Official Fix

Instructions:

🔧 Temporary Workarounds

Restrict Administrator Console Access

File Upload Restrictions

🧯 If You Can't Patch

🔍 How to Verify

Check if Vulnerable:

Check Version:

Verify Fix Applied:

📡 Detection & Monitoring

Log Indicators:

Network Indicators:

SIEM Query:

📊 Metadata

🔗 References

📤 Share & Export

🔗 Related Vulnerabilities