TA16-144A: WPAD Name Collision Vulnerability

Systems Affected

  • Windows, OS X, Linux systems, and web browsers with WPAD enabled
  • Networks using unregistered or unreserved TLDs

Overview

Web Proxy Auto-Discovery (WPAD) Domain Name System (DNS) queries that are intended for resolution on private or enterprise DNS servers have been observed reaching public DNS servers [1]. In combination with the new generic top level domain (gTLD) program’s incorporation of previously undelegated gTLDs for public registration, leaked WPAD queries could result in domain name collisions with internal network naming schemes [2] [3]. Opportunistic domain registrants could abuse these collisions by configuring external proxies for network traffic and enabling man-in-the-middle (MitM) attacks across the Internet.

Description

WPAD is a protocol used to ensure all systems in an organization use the same web proxy configuration. Instead of individually modifying configurations on each device connected to a network, WPAD locates a proxy configuration file and applies the configuration automatically.

The use of WPAD is enabled by default on all Microsoft Windows operating systems and Internet Explorer browsers. WPAD is supported but not enabled by default on Mac OS X and Linux-based operating systems, as well as Safari, Chrome, and Firefox browsers.

With the New gTLD program, previously undelegated gTLD strings are now being delegated for public domain name registration [3]. These strings may be used by private or enterprise networks, and in certain circumstances, such as when a work computer is connected from a home or external network, WPAD DNS queries may be made in error to public DNS servers. Attackers may exploit such leaked WPAD queries by registering the leaked domain and setting up MitM proxy configuration files on the Internet.

Other services (e.g., mail and internal web sites) may also perform DNS queries and attempt to automatically connect to supposedly internal DNS names [4].

Impact

Leaked WPAD queries could result in domain name collisions with internal network naming schemes. If an attacker registers a domain to answer leaked WPAD queries and configures a valid proxy, there is potential to conduct man-in-the-middle (MitM) attacks across the Internet.

The WPAD vulnerability is significant to corporate assets such as laptops. In some cases, these assets are vulnerable even while at work, but observations indicate that most assets become vulnerable when used outside an internal network (e.g., home networks, public Wi-Fi networks).

The impact of other types of leaked DNS queries and connection attempts varies depending on the type of service and its configuration.

Solution

References

Revisions

  • May 23, 2016: Initial Release
  • June 1, 2016: Added information on using TLDs restricted from registration with the gTLD program

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

TA16-132A: Exploitation of SAP Business Applications

Systems Affected

Outdated or misconfigured SAP systems

Overview

At least 36 organizations worldwide are affected by an SAP vulnerability [1]. Security researchers from Onapsis discovered indicators of exploitation against these organizations’ SAP business applications.

The observed indicators relate to the abuse of the Invoker Servlet, a built-in functionality in SAP NetWeaver Application Server Java systems (SAP Java platforms). The Invoker Servlet contains a vulnerability that was patched by SAP in 2010. However, the vulnerability continues to affect outdated and misconfigured SAP systems.

Description

SAP systems running outdated or misconfigured software are exposed to increased risks of malicious attacks.

The Invoker Servlet vulnerability affects business applications running on SAP Java platforms.

SAP Java platforms are the base technology stack for many SAP business applications and technical components, including:

  • SAP Enterprise Resource Planning (ERP),
  • SAP Product Lifecycle Management (PLM),
  • SAP Customer Relationship Management (CRM),
  • SAP Supply Chain Management (SCM),
  • SAP Supplier Relationship Management (SRM),
  • SAP NetWeaver Business Warehouse (BW),
  • SAP Business Intelligence (BI),
  • SAP NetWeaver Mobile Infrastructure (MI),
  • SAP Enterprise Portal (EP),
  • SAP Process Integration (PI),
  • SAP Exchange Infrastructure (XI),
  • SAP Solution Manager (SolMan),
  • SAP NetWeaver Development Infrastructure (NWDI),
  • SAP Central Process Scheduling (CPS),
  • SAP NetWeaver Composition Environment (CE),
  • SAP NetWeaver Enterprise Search,
  • SAP NetWeaver Identity Management (IdM), and
  • SAP Governance, Risk & Control 5.x (GRC).

The vulnerability resides on the SAP application layer, so it is independent of the operating system and database application that support the SAP system.

Impact

Exploitation of the Invoker Servlet vulnerability gives unauthenticated remote attackers full access to affected SAP platforms, providing complete control of the business information and processes on these systems, as well as potential access to other systems.

Solution

In order to mitigate this vulnerability, US-CERT recommends users and administrators implement SAP Security Note 1445998 and disable the Invoker Servlet. For more mitigation details, please review the Onapsis threat report [1].

In addition, US-CERT encourages that users and administrators:

  • Scan systems for all known vulnerabilities, such as missing security patches and dangerous system configurations.
  • Identify and analyze the security settings of SAP interfaces between systems and applications to understand risks posed by these trust relationships.
  • Analyze systems for malicious or excessive user authorizations.
  • Monitor systems for indicators of compromise resulting from the exploitation of vulnerabilities.
  • Monitor systems for suspicious user behavior, including both privileged and non-privileged users.
  • Apply threat intelligence on new vulnerabilities to improve the security posture against advanced targeted attacks.
  • Define comprehensive security baselines for systems and continuously monitor for compliance violations and remediate detected deviations.

These recommendations apply to SAP systems in public, private, and hybrid cloud environments.

Note: The U.S. Government does not endorse or support any particular product or vendor.

References

Revisions

  • May 11, 2016: Initial Release

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