Original release date: December 01, 2016 | Last revised: December 14, 2016
“Avalanche” refers to a large global network hosting infrastructure used by cyber criminals to conduct phishing and malware distribution campaigns and money mule schemes. The United States Department of Homeland Security (DHS), in collaboration with the Federal Bureau of Investigation (FBI), is releasing this Technical Alert to provide further information about Avalanche.
Cyber criminals utilized Avalanche botnet infrastructure to host and distribute a variety of malware variants to victims, including the targeting of over 40 major financial institutions. Victims may have had their sensitive personal information stolen (e.g., user account credentials). Victims’ compromised systems may also have been used to conduct other malicious activity, such as launching denial-of-service (DoS) attacks or distributing malware variants to other victims’ computers.
In addition, Avalanche infrastructure was used to run money mule schemes where criminals recruited people to commit fraud involving transporting and laundering stolen money or merchandise.
Avalanche used fast-flux DNS, a technique to hide the criminal servers, behind a constantly changing network of compromised systems acting as proxies.
The following malware families were hosted on the infrastructure:
Avalanche was also used as a fast flux botnet which provides communication infrastructure for other botnets, including the following:
QakBot (aka Qbot, PinkSlip Bot)
A system infected with Avalanche-associated malware may be subject to malicious activity including the theft of user credentials and other sensitive data, such as banking and credit card information. Some of the malware had the capability to encrypt user files and demand a ransom be paid by the victim to regain access to those files. In addition, the malware may have allowed criminals unauthorized remote access to the infected computer. Infected systems could have been used to conduct distributed denial-of-service (DDoS) attacks.
Users are advised to take the following actions to remediate malware infections associated with Avalanche:
Use and maintain anti-virus software – Anti-virus software recognizes and protects your computer against most known viruses. Even though parts of Avalanche are designed to evade detection, security companies are continuously updating their software to counter these advanced threats. Therefore, it is important to keep your anti-virus software up-to-date. If you suspect you may be a victim of an Avalanche malware, update your anti-virus software definitions and run a full-system scan. (See Understanding Anti-Virus Software for more information.)
Avoid clicking links in email – Attackers have become very skilled at making phishing emails look legitimate. Users should ensure the link is legitimate by typing the link into a new browser (see Avoiding Social Engineering and Phishing Attacks for more information).
Change your passwords – Your original passwords may have been compromised during the infection, so you should change them. (See Choosing and Protecting Passwords for more information.)
Keep your operating system and application software up-to-date – Install software patches so that attackers cannot take advantage of known problems or vulnerabilities. You should enable automatic updates of the operating system if this option is available. (See Understanding Patches for more information.)
Use anti-malware tools – Using a legitimate program that identifies and removes malware can help eliminate an infection. Users can consider employing a remediation tool. A non-exhaustive list of examples is provided below. The U.S. Government does not endorse or support any particular product or vendor.
Original release date: October 14, 2016 | Last revised: November 30, 2016
Internet of Things (IoT)—an emerging network of devices (e.g., printers, routers, video cameras, smart TVs) that connect to one another via the Internet, often automatically sending and receiving data
Recently, IoT devices have been used to create large-scale botnets—networks of devices infected with self-propagating malware—that can execute crippling distributed denial-of-service (DDoS) attacks. IoT devices are particularly susceptible to malware, so protecting these devices and connected hardware is critical to protect systems and networks.
On September 20, 2016, Brian Krebs’ security blog (krebsonsecurity.com) was targeted by a massive DDoS attack, one of the largest on record, exceeding 620 gigabits per second (Gbps).[1 (link is external)] An IoT botnet powered by Mirai malware created the DDoS attack. The Mirai malware continuously scans the Internet for vulnerable IoT devices, which are then infected and used in botnet attacks. The Mirai bot uses a short list of 62 common default usernames and passwords to scan for vulnerable devices. Because many IoT devices are unsecured or weakly secured, this short dictionary allows the bot to access hundreds of thousands of devices.[2 (link is external)] The purported Mirai author claimed that over 380,000 IoT devices were enslaved by the Mirai malware in the attack on Krebs’ website.[3 (link is external)]
In late September, a separate Mirai attack on French webhost OVH broke the record for largest recorded DDoS attack. That DDoS was at least 1.1 terabits per second (Tbps), and may have been as large as 1.5 Tbps.[4 (link is external)]
The IoT devices affected in the latest Mirai incidents were primarily home routers, network-enabled cameras, and digital video recorders.[5 (link is external)] Mirai malware source code was published online at the end of September, opening the door to more widespread use of the code to create other DDoS attacks.
In early October, Krebs on Security reported on a separate malware family responsible for other IoT botnet attacks.[6(link is external)] This other malware, whose source code is not yet public, is named Bashlite. This malware also infects systems through default usernames and passwords. Level 3 Communications, a security firm, indicated that the Bashlite botnet may have about one million enslaved IoT devices.[7 (link is external)]
With the release of the Mirai source code on the Internet, there are increased risks of more botnets being generated. Both Mirai and Bashlite can exploit the numerous IoT devices that still use default passwords and are easily compromised. Such botnet attacks could severely disrupt an organization’s communications or cause significant financial harm.
Software that is not designed to be secure contains vulnerabilities that can be exploited. Software-connected devices collect data and credentials that could then be sent to an adversary’s collection point in a back-end application.
In late November 2016, a new Mirai-derived malware attack actively scanned TCP port 7547 on broadband routers susceptible to a Simple Object Access Protocol (SOAP) vulnerability. [8 (link is external)] Affected routers use protocols that leave port 7547 open, which allows for exploitation of the router. These devices can then be remotely used in DDoS attacks. [9, 10 (links are external)]
Cybersecurity professionals should harden networks against the possibility of a DDoS attack. For more information on DDoS attacks, please refer to US-CERT Security Publication DDoS Quick Guide and the US-CERT Alert on UDP-Based Amplification Attacks.
In order to remove the Mirai malware from an infected IoT device, users and administrators should take the following actions:
Disconnect device from the network.
While disconnected from the network and Internet, perform a reboot. Because Mirai malware exists in dynamic memory, rebooting the device clears the malware [11 (link is external)].
Ensure that the password for accessing the device has been changed from the default password to a strong password. See US-CERT Tip Choosing and Protecting Passwords for more information.
You should reconnect to the network only after rebooting and changing the password. If you reconnect before changing the password, the device could be quickly reinfected with the Mirai malware.
In order to prevent a malware infection on an IoT device, users and administrators should take following precautions:
Ensure all default passwords are changed to strong passwords. Default usernames and passwords for most devices can easily be found on the Internet, making devices with default passwords extremely vulnerable.
Update IoT devices with security patches as soon as patches become available.
Purchase IoT devices from companies with a reputation for providing secure devices.
Consumers should be aware of the capabilities of the devices and appliances installed in their homes and businesses. If a device comes with a default password or an open Wi-Fi connection, consumers should change the password and only allow it to operate on a home network with a secured Wi-Fi router.
Understand the capabilities of any medical devices intended for at-home use. If the device transmits data or can be operated remotely, it has the potential to be infected.
Monitor Internet Protocol (IP) port 2323/TCP and port 23/TCP for attempts to gain unauthorized control over IoT devices using the network terminal (Telnet) protocol.[13 (link is external)]
Look for suspicious traffic on port 48101. Infected devices often attempt to spread malware by using port 48101 to send results to the threat actor.
Original release date: September 06, 2016 | Last revised: September 28, 2016
Network Infrastructure Devices
The advancing capabilities of organized hacker groups and cyber adversaries create an increasing global threat to information systems. The rising threat levels place more demands on security personnel and network administrators to protect information systems. Protecting the network infrastructure is critical to preserve the confidentiality, integrity, and availability of communication and services across an enterprise.
To address threats to network infrastructure devices, this Alert provides information on recent vectors of attack that advanced persistent threat (APT) actors are targeting, along with prevention and mitigation recommendations.
Network infrastructure consists of interconnected devices designed to transport communications needed for data, applications, services, and multi-media. Routers and firewalls are the focus of this alert; however, many other devices exist in the network, such as switches, load-balancers, intrusion detection systems, etc. Perimeter devices, such as firewalls and intrusion detection systems, have been the traditional technologies used to secure the network, but as threats change, so must security strategies. Organizations can no longer rely on perimeter devices to protect the network from cyber intrusions; organizations must also be able to contain the impact/losses within the internal network and infrastructure.
For several years now, vulnerable network devices have been the attack-vector of choice and one of the most effective techniques for sophisticated hackers and advanced threat actors. In this environment, there has never been a greater need to improve network infrastructure security. Unlike hosts that receive significant administrative security attention and for which security tools such as anti-malware exist, network devices are often working in the background with little oversight—until network connectivity is broken or diminished. Malicious cyber actors take advantage of this fact and often target network devices. Once on the device, they can remain there undetected for long periods. After an incident, where administrators and security professionals perform forensic analysis and recover control, a malicious cyber actor with persistent access on network devices can reattack the recently cleaned hosts. For this reason, administrators need to ensure proper configuration and control of network devices.
Proliferation of Threats to Information Systems
In September 2015, an attack known as SYNful Knock was disclosed. SYNful Knock silently changes a router’s operating system image, thus allowing attackers to gain a foothold on a victim’s network. The malware can be customized and updated once embedded. When the modified malicious image is uploaded, it provides a backdoor into the victim’s network. Using a crafted TCP SYN packet, a communication channel is established between the compromised device and the malicious command and control (C2) server. The impact of this infection to a network or device is severe and most likely indicates that there may be additional backdoors or compromised devices on the network. This foothold gives an attacker the ability to maneuver and infect other hosts and access sensitive data.
The initial infection vector does not leverage a zero-day vulnerability. Attackers either use the default credentials to log into the device or obtain weak credentials from other insecure devices or communications. The implant resides within a modified IOS image and, when loaded, maintains its persistence in the environment, even after a system reboot. Any further modules loaded by the attacker will only exist in the router’s volatile memory and will not be available for use after the device reboots. However, these devices are rarely or never rebooted.
To prevent the size of the image from changing, the malware overwrites several legitimate IOS functions with its own executable code. The attacker examines the functionality of the router and determines functions that can be overwritten without causing issues on the router. Thus, the overwritten functions will vary upon deployment.
The attacker can utilize the secret backdoor password in three different authentication scenarios. In these scenarios the implant first checks to see if the user input is the backdoor password. If so, access is granted. Otherwise, the implanted code will forward the credentials for normal verification of potentially valid credentials. This generally raises the least amount of suspicion. Cisco has provided an alert on this attack vector. For more information, see the Cisco SYNful Knock Security Advisory.
Other attacks against network infrastructure devices have also been reported, including more complicated persistent malware that silently changes the firmware on the device that is used to load the operating system so that the malware can inject code into the running operating system. For more information, please see Cisco's description of the evolution of attacks on Cisco IOS devices.
Cisco Adaptive Security Appliance (ASA)
A Cisco ASA device is a network device that provides firewall and Virtual Private Network (VPN) functionality. These devices are often deployed at the edge of a network to protect a site’s network infrastructure, and to give remote users access to protected local resources.
In June 2016, NCCIC received several reports of compromised Cisco ASA devices that were modified in an unauthorized way. The ASA devices directed users to a location where malicious actors tried to socially engineer the users into divulging their credentials.
It is suspected that malicious actors leveraged CVE-2014-3393 to inject malicious code into the affected devices. The malicious actor would then be able to modify the contents of the Random Access Memory Filing System (RAMFS) cache file system and inject the malicious code into the appliance’s configuration. Refer to the Cisco Security Advisory Multiple Vulnerabilities in Cisco ASA Software for more information and for remediation details.
In August 2016, a group known as “Shadow Brokers” publicly released a large number of files, including exploitation tools for both old and newly exposed vulnerabilities. Cisco ASA devices were found to be vulnerable to the released exploit code. In response, Cisco released an update to address a newly disclosed Cisco ASA Simple Network Management Protocol (SNMP) remote code execution vulnerability (CVE-2016-6366). In addition, one exploit tool targeted a previously patched Cisco vulnerability (CVE-2016-6367). Although Cisco provided patches to fix this Cisco ASA command-line interface (CLI) remote code execution vulnerability in 2011, devices that remain unpatched are still vulnerable to the described attack. Attackers may target vulnerabilities for months or even years after patches become available.
If the network infrastructure is compromised, malicious hackers or adversaries can gain full control of the network infrastructure enabling further compromise of other types of devices and data and allowing traffic to be redirected, changed, or denied. Possibilities of manipulation include denial-of-service, data theft, or unauthorized changes to the data.
Intruders with infrastructure privilege and access can impede productivity and severely hinder re-establishing network connectivity. Even if other compromised devices are detected, tracking back to a compromised infrastructure device is often difficult.
Malicious actors with persistent access to network devices can reattack and move laterally after they have been ejected from previously exploited hosts.
1. Segregate Networks and Functions
Proper network segmentation is a very effective security mechanism to prevent an intruder from propagating exploits or laterally moving around an internal network. On a poorly segmented network, intruders are able to extend their impact to control critical devices or gain access to sensitive data and intellectual property. Security architects must consider the overall infrastructure layout, segmentation, and segregation. Segregation separates network segments based on role and functionality. A securely segregated network can contain malicious occurrences, reducing the impact from intruders, in the event that they have gained a foothold somewhere inside the network.
Physical Separation of Sensitive Information
Local Area Network (LAN) segments are separated by traditional network devices such as routers. Routers are placed between networks to create boundaries, increase the number of broadcast domains, and effectively filter users’ broadcast traffic. These boundaries can be used to contain security breaches by restricting traffic to separate segments and can even shut down segments of the network during an intrusion, restricting adversary access.
Implement Principles of Least Privilege and need-to-know when designing network segments.
Separate sensitive information and security requirements into network segments.
Apply security recommendations and secure configurations to all network segments and network layers.
Virtual Separation of Sensitive Information
As technologies change, new strategies are developed to improve IT efficiencies and network security controls. Virtual separation is the logical isolation of networks on the same physical network. The same physical segmentation design principles apply to virtual segmentation but no additional hardware is required. Existing technologies can be used to prevent an intruder from breaching other internal network segments.
Use Private Virtual LANs to isolate a user from the rest of the broadcast domains.
Use Virtual Routing and Forwarding (VRF) technology to segment network traffic over multiple routing tables simultaneously on a single router.
Use VPNs to securely extend a host/network by tunneling through public or private networks.
2. Limit Unnecessary Lateral Communications
Allowing unfiltered workstation-to-workstation communications (as well as other peer-to-peer communications) creates serious vulnerabilities, and can allow a network intruder to easily spread to multiple systems. An intruder can establish an effective “beach head” within the network, and then spread to create backdoors into the network to maintain persistence and make it difficult for defenders to contain and eradicate.
Restrict communications using host-based firewall rules to deny the flow of packets from other hosts in the network. The firewall rules can be created to filter on a host device, user, program, or IP address to limit access from services and systems.
Implement a VLAN Access Control List (VACL), a filter that controls access to/from VLANs. VACL filters should be created to deny packets the ability to flow to other VLANs.
Logically segregate the network using physical or virtual separation allowing network administrators to isolate critical devices onto network segments.
3. Harden Network Devices
A fundamental way to enhance network infrastructure security is to safeguard networking devices with secure configurations. Government agencies, organizations, and vendors supply a wide range of resources to administrators on how to harden network devices. These resources include benchmarks and best practices. These recommendations should be implemented in conjunction with laws, regulations, site security policies, standards, and industry best practices. These guides provide a baseline security configuration for the enterprise that protects the integrity of network infrastructure devices. This guidance supplements the network security best practices supplied by vendors.
Disable unencrypted remote admin protocols used to manage network infrastructure (e.g., Telnet, FTP).
Use SNMPv3 (or subsequent version) but do not use SNMP community strings.
Secure access to the console, auxiliary, and VTY lines.
Implement robust password policies and use the strongest password encryption available.
Protect router/switch by controlling access lists for remote administration.
Restrict physical access to routers/switches.
Backup configurations and store offline. Use the latest version of the network device operating system and update with all patches.
Periodically test security configurations against security requirements.
Protect configuration files with encryption and/or access controls when sending them electronically and when they are stored and backed up.
4. Secure Access to Infrastructure Devices
Administrative privileges on infrastructure devices allow access to resources that are normally unavailable to most users and permit the execution of actions that would otherwise be restricted. When administrator privileges are improperly authorized, granted widely, and/or not closely audited, intruders can exploit them. These compromised privileges can enable adversaries to traverse a network, expanding access and potentially allowing full control of the infrastructure backbone. Unauthorized infrastructure access can be mitigated by properly implementing secure access policies and procedures.
Implement Multi-Factor Authentication – Authentication is a process to validate a user’s identity. Weak authentication processes are commonly exploited by attackers. Multi-factor authentication uses at least two identity components to authenticate a user’s identity. Identity components include something the user knows (e.g., password); an object the user has possession of (e.g., token); and a trait unique to the specific person (e.g., biometric).
Manage Privileged Access – Use an authorization server to store access information for network device management. This type of server will enable network administrators to assign different privilege levels to users based on the principle of least privilege. When a user tries to execute an unauthorized command, it will be rejected. To increase the strength and robustness of user authentication, implement a hard token authentication server in addition to the AAA server, if possible. Multi-factor authentication increases the difficulty for intruders to steal and reuse credentials to gain access to network devices.
Manage Administrative Credentials – Although multi-factor authentication is highly recommended and a best practice, systems that cannot meet this requirement can at least improve their security level by changing default passwords and enforcing complex password policies. Network accounts must contain complex passwords of at least 14 characters from multiple character domains including lowercase, uppercase, numbers, and special characters. Enforce password expiration and reuse policies. If passwords are stored for emergency access, keep these in a protected off-network location, such as a safe.
5. Perform Out-of-Band Management
Out-of-Band (OoB) management uses alternate communication paths to remotely manage network infrastructure devices. These dedicated paths can vary in configuration to include anything from virtual tunneling to physical separation. Using OoB access to manage the network infrastructure will strengthen security by limiting access and separating user traffic from network management traffic. OoB management provides security monitoring and can implement corrective actions without allowing the adversary who may have already compromised a portion of the network to observe these changes.
OoB management can be implemented physically or virtually, or through a hybrid of the two. Building additional physical network infrastructure is the most secure option for the network managers, although it can be very expensive to implement and maintain. Virtual implementation is less costly, but still requires significant configuration changes and administration. In some situations, such as access to remote locations, virtual encrypted tunnels may be the only viable option.
Segregate standard network traffic from management traffic.
Enforce that management traffic on devices only comes from the OoB.
Apply encryption to all management channels.
Encrypt all remote access to infrastructure devices such as terminal or dial-in servers.
Manage all administrative functions from a dedicated host (fully patched) over a secure channel, preferably on the OoB.
Harden network management devices by testing patches, turning off unnecessary services on routers and switches, and enforcing strong password policies. Monitor the network and review logs Implement access controls that only permit required administrative or management services (SNMP, NTP SSH, FTP, TFTP).
6. Validate Integrity of Hardware and Software
Products purchased through unauthorized channels are often known as “counterfeit,” “secondary,” or “grey market” devices. There have been numerous reports in the press regarding grey market hardware and software being introduced into the marketplace. Grey market products have not been thoroughly tested to meet quality standards and can introduce risks to the network. Lack of awareness or validation of the legitimacy of hardware and software presents a serious risk to users’ information and the overall integrity of the network environment. Products purchased from the secondary market run the risk of having the supply chain breached, which can result in the introduction of counterfeit, stolen, or second-hand devices. This could affect network performance and compromise the confidentiality, integrity, or availability of network assets. Furthermore, breaches in the supply chain provide an opportunity for malicious software or hardware to be installed on the equipment. In addition, unauthorized or malicious software can be loaded onto a device after it is in operational use, so integrity checking of software should be done on a regular basis.
Maintain strict control of the supply chain; purchase only from authorized resellers.
Require resellers to implement a supply chain integrity check to validate hardware and software authenticity.
Inspect the device for signs of tampering.
Validate serial numbers from multiple sources.
Download software, updates, patches, and upgrades from validated sources.
Perform hash verification and compare values against the vendor’s database to detect unauthorized modification to the firmware.
Monitor and log devices, verifying network configurations of devices on a regular schedule.
Train network owners, administrators, and procurement personnel to increase awareness of grey market devices.
All Symantec and Norton branded antivirus products
Symantec and Norton branded antivirus products contain multiple vulnerabilities. Some of these products are in widespread use throughout government and industry. Exploitation of these vulnerabilities could allow a remote attacker to take control of an affected system.
Symantec antivirus products use common unpackers to extract malware binaries when scanning a system. A heap overflow vulnerability in the ASPack unpacker could allow an unauthenticated remote attacker to gain root privileges on Linux or OSX platforms. The vulnerability can be triggered remotely using a malicious file (via email or link) with no user interaction. 
Symantec: missing bounds checks in dec2zip ALPkOldFormatDecompressor::UnShrink 
The large number of products affected (24 products), across multiple platforms (OSX, Windows, and Linux), and the severity of these vulnerabilities (remote code execution at root or SYSTEM privilege) make this a very serious event. A remote, unauthenticated attacker may be able to run arbitrary code at root or SYSTEM privileges by taking advantage of these vulnerabilities. Some of the vulnerabilities require no user interaction and are network-aware, which could result in a wormable-event.
Symantec has provided patches or hotfixes to these vulnerabilities in their SYM16-008  and SYM16-010  security advisories.
US-CERT encourages users and network administrators to patch Symantec or Norton antivirus products immediately. While there has been no evidence of exploitation, the ease of attack, widespread nature of the products, and severity of the exploit may make this vulnerability a popular target.
Original release date: May 23, 2016 | Last revised: October 06, 2016
Windows, OS X, Linux systems, and web browsers with WPAD enabled
Networks using unregistered or unreserved TLDs
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 . 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  . 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.
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 . 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 .
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.
US-CERT encourages users and network administrators to implement the following recommendations to provide a more secure and efficient network infrastructure:
Consider disabling automatic proxy discovery/configuration in browsers and operating systems unless those systems will only be used on internal networks.
Consider using a registered and fully qualified domain name (FQDN) from global DNS as the root for enterprise and other internal namespace.
Consider using an internal TLD that is under your control and restricted from registration with the new gTLD program. Note that there is no assurance that the current list of “Reserved Names” from the new gTLD Applicant Guidebook (AGB) will remain reserved with subsequent rounds of new gTLDs .
Configure internal DNS servers to respond authoritatively to internal TLD queries.
Configure firewalls and proxies to log and block outbound requests for wpad.dat files.
Identify expected WPAD network traffic and monitor the public namespace or consider registering domains defensively to avoid future name collisions.
Original release date: May 11, 2016 | Last revised: September 29, 2016
Outdated or misconfigured SAP systems
At least 36 organizations worldwide are affected by an SAP vulnerability . 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.
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.
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.
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 .
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.