US CERT: Technical Security Alerts

Original release date: June 17, 2019
Summary

The Cybersecurity and Infrastructure Security Agency (CISA) is issuing this Activity Alert to provide information on a vulnerability, known as “BlueKeep,” that exists in the following Microsoft Windows Operating Systems (OSs), including both 32- and 64-bit versions, as well as all Service Pack versions:

• Windows 2000
• Windows Vista
• Windows XP
• Windows 7
• Windows Server 2003
• Windows Server 2003 R2
• Windows Server 2008
• Windows Server 2008 R2

An attacker can exploit this vulnerability to take control of an affected system.     

Technical Details

BlueKeep (CVE-2019-0708) exists within the Remote Desktop Protocol (RDP) used by the Microsoft Windows OSs listed above. An attacker can exploit this vulnerability to perform remote code execution on an unprotected system. 

According to Microsoft, an attacker can send specially crafted packets to one of these operating systems that has RDP enabled.[1] After successfully sending the packets, the attacker would have the ability to perform a number of actions: adding accounts with full user rights; viewing, changing, or deleting data; or installing programs. This exploit, which requires no user interaction, must occur before authentication to be successful.

BlueKeep is considered “wormable” because malware exploiting this vulnerability on a system could propagate to other vulnerable systems; thus, a BlueKeep exploit would be capable of rapidly spreading in a fashion similar to the WannaCry malware attacks of 2017.[2]

CISA has coordinated with external stakeholders and determined that Windows 2000 is vulnerable to BlueKeep.

Mitigations

CISA encourages users and administrators review the Microsoft Security Advisory [3] and the Microsoft Customer Guidance for CVE-2019-0708 [4] and apply the appropriate mitigation measures as soon as possible:

• Install available patches. Microsoft has released security updates to patch this vulnerability. Microsoft has also released patches for a number of OSs that are no longer officially supported, including Windows Vista, Windows XP, and Windows Server 2003. As always, CISA encourages users and administrators to test patches before installation.

For OSs that do not have patches or systems that cannot be patched, other mitigation steps can be used to help protect against BlueKeep:

• Upgrade end-of-life (EOL) OSs. Consider upgrading any EOL OSs no longer supported by Microsoft to a newer, supported OS, such as Windows 10.
• Disable unnecessary services. Disable services not being used by the OS. This best practice limits exposure to vulnerabilities.  
• Enable Network Level Authentication. Enable Network Level Authentication in Windows 7, Windows Server 2008, and Windows Server 2008 R2. Doing so forces a session request to be authenticated and effectively mitigates against BlueKeep, as exploit of the vulnerability requires an unauthenticated session.
• Block Transmission Control Protocol (TCP) port 3389 at the enterprise perimeter firewall. Because port 3389 is used to initiate an RDP session, blocking it prevents an attacker from exploiting BlueKeep from outside the user’s network. However, this will block legitimate RDP sessions and may not prevent unauthenticated sessions from being initiated inside a network.

References

• [1] Microsoft Security Advisory for CVE-2019-0708
• [2] White House Press Briefing on the Attribution of the WannaCry Malware Attack to North Korea
• [3] Microsoft Security Advisory for CVE-2019-0708
• [4] Microsoft Customer Guidance for CVE-2019-0708

Revisions

• June 17, 2019: Initial version
• June 17, 2019: Revised technical details section.

This product is provided subject to this Notification and this Privacy & Use policy.

Original release date: June 17, 2019
Summary

The Cybersecurity and Infrastructure Security Agency (CISA) is issuing this Activity Alert to provide information on a vulnerability, known as “BlueKeep,” that exists in the following Microsoft Windows Operating Systems (OSs), including both 32- and 64-bit versions, as well as all Service Pack versions:

• Windows 2000
• Windows Vista
• Windows XP
• Windows 7
• Windows Server 2003
• Windows Server 2003 R2
• Windows Server 2008
• Windows Server 2008 R2

An attacker can exploit this vulnerability to take control of an affected system.     

Technical Details

BlueKeep (CVE-2019-0708) exists within the Remote Desktop Protocol (RDP) used by the Microsoft Windows OSs listed above. An attacker can exploit this vulnerability to perform remote code execution on an unprotected system. 

According to Microsoft, an attacker can send specially crafted packets to one of these operating systems that has RDP enabled.[1] After successfully sending the packets, the attacker would have the ability to perform a number of actions: adding accounts with full user rights; viewing, changing, or deleting data; or installing programs. This exploit, which requires no user interaction, must occur before authentication to be successful.

BlueKeep is considered “wormable” because malware exploiting this vulnerability on a system could propagate to other vulnerable systems; thus, a BlueKeep exploit would be capable of rapidly spreading in a fashion similar to the WannaCry malware attacks of 2017.[2]

CISA tested BlueKeep against a Windows 2000 machine and achieved remote code execution. Windows OS versions prior to Windows 8 that are not mentioned in this Activity Alert may also be affected; however, CISA has not tested these systems.  

Mitigations

CISA encourages users and administrators review the Microsoft Security Advisory [3] and the Microsoft Customer Guidance for CVE-2019-0708 [4] and apply the appropriate mitigation measures as soon as possible:

• Install available patches. Microsoft has released security updates to patch this vulnerability. Microsoft has also released patches for a number of OSs that are no longer officially supported, including Windows Vista, Windows XP, and Windows Server 2003. As always, CISA encourages users and administrators to test patches before installation.

For OSs that do not have patches or systems that cannot be patched, other mitigation steps can be used to help protect against BlueKeep:

• Upgrade end-of-life (EOL) OSs. Consider upgrading any EOL OSs no longer supported by Microsoft to a newer, supported OS, such as Windows 10.
• Disable unnecessary services. Disable services not being used by the OS. This best practice limits exposure to vulnerabilities.  
• Enable Network Level Authentication. Enable Network Level Authentication in Windows 7, Windows Server 2008, and Windows Server 2008 R2. Doing so forces a session request to be authenticated and effectively mitigates against BlueKeep, as exploit of the vulnerability requires an unauthenticated session.
• Block Transmission Control Protocol (TCP) port 3389 at the enterprise perimeter firewall. Because port 3389 is used to initiate an RDP session, blocking it prevents an attacker from exploiting BlueKeep from outside the user’s network. However, this will block legitimate RDP sessions and may not prevent unauthenticated sessions from being initiated inside a network.

References

• [1] Microsoft Security Advisory for CVE-2019-0708
• [2] White House Press Briefing on the Attribution of the WannaCry Malware Attack to North Korea
• [3] Microsoft Security Advisory for CVE-2019-0708
• [4] Microsoft Customer Guidance for CVE-2019-0708

Revisions

• June 17, 2019: Initial version

This product is provided subject to this Notification and this Privacy & Use policy.

Original release date: May 2, 2019 | Last revised: May 3, 2019
Summary

The Cybersecurity and Infrastructure Security Agency (CISA) is issuing this activity alert in response to recently disclosed exploits that target unsecure configurations of SAP components. [1]

Technical Details

A presentation at the April 2019 Operation for Community Development and Empowerment (OPCDE) cybersecurity conference describes SAP systems with unsecure configurations exposed to the internet. Typically, SAP systems are not intended to be exposed to the internet as it is an untrusted network. Malicious cyber actors can attack and compromise these unsecure systems with publicly available exploit tools, termed “10KBLAZE.” The presentation details the new exploit tools and reports on systems exposed to the internet.

SAP Gateway ACL

The SAP Gateway allows non-SAP applications to communicate with SAP applications. If SAP Gateway access control lists (ACLs) are not configured properly (e.g., gw/acl_mode = 0), anonymous users can run operating system (OS) commands.[2] According to the OPCDE presentation, about 900 U.S. internet-facing systems were detected in this vulnerable condition.

SAP Router secinfo

The SAP router is a program that helps connect SAP systems with external networks. The default secinfo configuration for a SAP Gateway allows any internal host to run OS commands anonymously. If an attacker can access a misconfigured SAP router, the router can act as an internal host and proxy the attacker’s requests, which may result in remote code execution.

According to the OPCDE presentation, 1,181 SAP routers were exposed to the internet. It is unclear if the exposed systems were confirmed to be vulnerable or were simply running the SAP router service.

SAP Message Server

SAP Message Servers act as brokers between Application Servers (AS). By default, Message Servers listen on a port 39XX and have no authentication. If an attacker can access a Message Server, they can redirect and/or execute legitimate man-in-the-middle (MITM) requests, thereby gaining credentials. Those credentials can be used to execute code or operations on AS servers (assuming the attacker can reach them). According to the OPCDE presentation, there are 693 Message Servers exposed to the internet in the United States. The Message Server ACL must be protected by the customer in all releases.

Signature

CISA worked with security researchers from Onapsis Inc.[3] to develop the following Snort signature that can be used to detect the exploits:

alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"10KBLAZE SAP Exploit execute attempt"; flow:established,to_server; content:"|06 cb 03|"; offset:4; depth:3; content:"SAPXPG_START_XPG"; nocase; distance:0; fast_pattern; content:"37D581E3889AF16DA00A000C290099D0001"; nocase; distance:0; content:"extprog"; nocase; distance:0; sid:1; rev:1;)

 

Mitigations

CISA recommends administrators of SAP systems implement the following to mitigate the vulnerabilities included in the OPCDE presentation:

• Ensure a secure configuration of their SAP landscape.
• Restrict access to SAP Message Server.
  • Review SAP Notes 1408081 and 821875. Restrict authorized hosts via ACL files on Gateways (gw/acl_mode and secinfo) and Message Servers (ms/acl_info).[4], [5]
  • Review SAP Note 1421005. Split MS internal/public: rdisp/msserv=0 rdisp/msserv_internal=39NN. [6]
  • Restrict access to Message Server internal port (tcp/39NN) to clients or the internet.
  • Enable Secure Network Communications (SNC) for clients.
• Scan for exposed SAP components.
  • Ensure that SAP components are not exposed to the internet.
  • Remove or secure any exposed SAP components.

References

• [1] Comae Technologies: Operation for Community Development and Empowerment (OPCDE) Cybersecurity Conference Materials
• [2] SAP: Gateway Access Control Lists
• [3] Onapsis Inc. website
• [4] SAP Note 1408081
• [5] SAP Note 821875
• [6] SAP Note 1421005

Revisions

• May 2, 2019: Initial version

This product is provided subject to this Notification and this Privacy & Use policy.

Original release date: May 02, 2019
Summary

The Cybersecurity and Infrastructure Security Agency (CISA) is issuing this activity alert in response to recently disclosed exploits that target unsecure configurations of SAP components. [1]

Technical Details

A presentation at the April 2019 Operation for Community Development and Empowerment (OPCDE) cybersecurity conference describes SAP systems with unsecure configurations exposed to the internet. Typically, SAP systems are not intended to be exposed to the internet, as it is an untrusted network. Malicious cyber actors can attack and compromise these unsecure systems with publicly available exploit tools, termed “10KBLAZE.” The presentation detailed the new exploit tools and reports on systems exposed to the internet.

SAP Gateway ACL

The SAP Gateway allows non-SAP applications to communicate with SAP applications using the Open Data Protocol (OData). If SAP Gateway access control lists (ACLs) are not configured properly (e.g., gw/acl_mode = 0), anonymous users can run operating system (OS) commands.[2] According to the OPCDE presentation, about 900 U.S. internet-facing systems were detected in this vulnerable condition.

SAP Router secinfo

The SAP router is a program that helps connect SAP systems with external networks. The default secinfo configuration for a SAP Gateway allows any internal host to run OS commands anonymously. If an attacker can access an SAP router, the router can act as an internal host and proxy the attacker’s requests, which may result in remote code execution.

According to the OPCDE presentation, 1,181 SAP routers were exposed to the internet. It is unclear if the exposed systems were confirmed to be vulnerable or were simply running the SAP router service.

SAP Message Server

SAP Message Servers act as brokers between Application Servers (AS). By default, Message Servers listen on a port 39XX and have no authentication. If an attacker can access a Message Server, they can redirect and/or execute legitimate man-in-the-middle (MITM) requests, thereby gaining credentials. Those credentials can be used to execute code or operations on AS servers (assuming the attacker can reach them). According to the OPCDE presentation, there are 693 Message Servers exposed to the internet in the United States.

Signature

CISA worked with security researchers from Onapsis Inc.[3] to develop the following Snort signature that can be used to detect the exploits:

alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"10KBLAZE SAP Exploit execute attempt"; flow:established,to_server; content:"|06 cb 03|"; offset:4; depth:3; content:"SAPXPG_START_XPG"; nocase; distance:0; fast_pattern; content:"37D581E3889AF16DA00A000C290099D0001"; nocase; distance:0; content:"extprog"; nocase; distance:0; sid:1; rev:1;)

 

Mitigations

CISA recommends administrators of SAP systems implement the following to mitigate the vulnerabilities included in the OPCDE presentation:

• Ensure a secure configuration of their SAP landscape
• Restrict access to SAP Message Server.
  • Review SAP Notes 1408081 and 821875. Restrict authorized hosts via ACL files on Gateways (gw/acl_mode and secinfo) and Message Servers (ms/acl_info).[4], [5]
  • Review SAP Note 1421005. Split MS internal/public: rdisp/msserv=0 rdisp/msserv_internal=39NN. [6]
  • Restrict access to Message Server internal port (tcp/39NN) to clients or the internet.
  • Enable Secure Network Communications (SNC) for clients.
• Scan for exposed SAP components.
  • Ensure that SAP components are not exposed to the internet.
  • Remove or secure any exposed SAP components.

References

• [1] Comae Technologies Operation for Community Development and Empowerment (OPCDE) Cybersecurity Conference Materials
• [2] SAP: Gateway Access Control Lists
• [3] Onapsis Inc. website
• [4] SAP Note 1408081
• [5] SAP Note 821875
• [6] SAP Note 1421005

Revisions

• May 2, 2019: Initial version

This product is provided subject to this Notification and this Privacy & Use policy.