Layer Seven Security

White Hats, Black Hats and Skiddies: The Class System in Information Security

There are few terms more widely misunderstood in the world of information security than the word ‘hacking’. Although it’s used in a variety of contexts, it’s most commonly used to refer to all types of cyber crime including everything from fraud and industrial espionage to identity theft and spamming. If you take this view, cyber crimes are the deeds of ‘hackers’.

In reality, hackers do far more good than harm. Many are researchers that practice a form of ethical hacking driven by a desire to improve the state of information security. Ethical hackers are the ‘white hats’ of security. They use everything from port scanning to breaking and entering to simulate an attack against networks and systems, usually with the consent of their targets. Software companies such as SAP owe a huge debt to white hats. Many of the vulnerabilities patched by SAP Security Notes are discovered not by SAP, but independent researchers that are far more adept at finding vulnerabilities than SAP itself.

In the past, white hats would publish details about vulnerabilities as soon as they were discovered. Today, most follow SAP’s Disclosure Guidelines. As a result, very few vulnerabilities are publicized until they are patched by SAP. Whether or not this is in the interest of SAP customers is open to debate. It could be argued that this reduces the incentive for SAP to properly patch its software, A case in point is a session hijacking vulnerability in the Enterprise Portal which wasn’t patched until 18 months after it was reported to SAP.

White hats rule the roost of information security. One step below are the black hats who most closely resemble the stereotypical image of hackers portrayed in pop culture. Black hats use the same tactics as white hats but differ in their motives which are generally malicious. Most are driven by the need for notoriety or personal gain, although some are motivated by more noble goals such as social justice. The latter are often referred to as ‘hacktivits’. Its difficult to stall an attack by talented and determined black hats. The only approach that provides any glimmer of hope is the tried and tested defense-in-depth strategy which may buy enough time to detect a breach before any real damage is done or encourage attackers to direct their efforts towards other less well defended targets outside your network.

White hats look down upon black hats but the two groups have much in common. Firstly, they are both skilled in the art of finding and exploiting vulnerabilities. Secondly, they’re partial to challenges and venerate well-constructed code like a thing of beauty. Thirdly, both white hats and black hats frown upon script kiddies, or skiddies for short.

Skiddies are the hillbillies of the information security world. They don’t look down upon anyone since they’re at the rock bottom of the totem pole. Skiddies are considered social pariahs since they have no appreciation of the concepts and tools of information security. Their sole purpose is to exploit vulnerabilities discovered by black hats. Black hats take pride in their work. Targets are carefully selected and attacks are meticulously planned. They go to great lengths to cover up their tracks. Skiddies, on the other hand, blindly execute scripts developed by black hats hoping to catch victims that happen to be susceptible to whatever vulnerability they’re targeting at a moment in time. Despite this, skiddies should not be underestimated. They far out-number black hats. They also have an uncanny ability to learn about new exploits long before they’re patched. This is fuelled by IRC (Internet Relay Chat) and online trading for zero-day exploits.

The proliferation of easy to use security tools with point and click interfaces has dumbed down hacking and turned the tide in favor of skiddies. Many programming or configuration flaws in systems such as SAP don’t require any technical skill to exploit. Therefore, relying upon security through obscurity no longer works, especially when systems are public-facing.

Intense, focused attacks led by black hats are destructive but far less likely than a random strike performed by a skiddie. However, the latter will quickly reveal vulnerabilities in a poorly patched SAP environment.

The Top 5 Security Notes you should apply to Patch your SAP systems

April was another bumper month for SAP Security Notes. In all, SAP issued 33 patches, of which 5 were considered critical. Top of the list were Notes 1647225 and 1675432 which address missing authorization checks in components of Business Objects Data Services (EIM-DS) and the SAP Classification System (CA-CL).

EIM-DS is SAP’s flagship solution for data integration and quality. It’s used to consolidate, cleanse and migrate data from both SAP and external systems. CA-CL is used to manage classification properties and classes for various types of objects. An example could be an object such as a Ford F-350. This would fall into a Vehicle class and have properties such as length, weight, color, power, capacity, etc. assigned within the system. Both EIM-DS and CA-CL suffer from vulnerabilities that could enable users to escalate their privileges and perform administrative functions.

SAP also issued three other critical Security Notes. Two of these deal with programming errors in the SAP User Management Engine (BC-JAS-SEC) and other components of the NetWeaver Web AS Java. This manages Web-based access to SAP applications such as the Enterprise Portal. Note 1651004 is designed to protect the UME from cross-frame scripting (XFS) attacks that could be used to the steal the logon credentials of SAP users. You can learn more about XFS here. Note 1641208 deals with signature wrapping attacks that target XML messages transmitted through certain SAP Web services. This attack can be used to intercept and manipulate a message without breaking the digital signature designed to protect the integrity of the message and its content. It could enable attackers to modify the data within XML messages without detection.

The last vital patch released by SAP in April was Note 1652803 which fixes a Denial of Service (DoS) vulnerability in certain versions of Apache Tomcat bundled with Business Objects Enterprise. Tomcat is an open source web server that provides a runtime environment for Java code. Business Objects Enterprise is the platform that supports SAP reporting tools such as Crystal Reports, Web Intelligence and the Dashboard Builder.

SAP uses the Common Vulnerability Scoring System (CVSS) system to rate Security Notes. Three of the five critical vulnerabilities patched in April have a base score of 7.5. The highest possible score is 10.0. SAP did not provide CVSS information for the other two. This is fairly common. SAP doesn’t consistently provide CVSS scores for all Notes.

The Advisory below includes a complete listing of all of the Security Notes issued by SAP last month. Particular attention should be paid to 1657200, which is designed to patch a flaw in an SAP component responsible for managing payment cards, and the injection vulnerability patched by 1638596.

The Four Myths of ERP Security

There are several myths in ERP security. One of the most common is that security is largely a matter of controlling access and segregation of duties. Another is that business applications are accessible only within internal networks. Yet another is that such applications are not a target for attack. All three are based on a simplistic and misguided take on today’s ERP systems.

The reality is that contemporary ERP systems have a highly complex structure. Complexity is the enemy of security. Vulnerabilities can be found not only in the business or application layer (which is the traditional area of focus for ERP security practitioners) but the technical layer that includes database, operating system and network components. A Fort Knox approach for the application level will provide a false sense of security if architectural,  configuration and programming flaws are not addressed at the technical level.

This is compounded by the fact that most ERP instances have more than one attack surface. Almost all have direct or indirect connections to the Internet. The former includes connections to external offices, suppliers, vendors or other partners and to SAP services. The latter can include connections to user workstations with Web access. ERP resources are increasingly designed to be accessible by mobile users using Web-based protocols, ports and services. The isolated mainframes of yesteryear are a distant memory in our era of global communications.

Vectors for attack surfaces in ERP systems are generally well-known. What’s more, most can be performed with low-spec laptops and minimal technical knowledge. The idea that very few people have any motive to attack such information-rich systems is one of the most disturbing and perplexing myths in ERP security. I’m reminded of a comment that was made to me by a prominent partner in a well-known consulting firm. The partner was engaged as a security advisor by a large meat processing company during an otherwise successful SAP implementation. In his view, the client had a relatively low risk profile which justified a ‘vanilla’ security framework for its SAP systems. As a result, the company was urged to stick with SAP defaults, wherever possible.

The leads to the fourth and most damaging myth in ERP security: the notion that systems are securely configured by default and, where they are not, it’s the responsibility of the vendor to secure the system. ERP systems are designed to be flexible. They have to be capable of meeting the diverse needs of every imaginable business in all industries and sectors. As a result, there is no standard configuration that can meet the requirements of every business. Security has to be enabled. Default security settings are often highly dangerous and can leave organizations open to internal and external attacks. For this reason, SAP has issued numerous white papers, security guides and other publications to support the secure configuration of its software during and after implementation. This should be required reading for all security professionals specializing in SAP.

SAP does not take responsibility for security issues arising from architectural flaws, misconfigurations and inadequate patching. Customers are expected to design, manage and maintain their systems in a secure manner. This can prove to be a challenge in companies where there is no clear ownership over SAP resources or in cases where systems are owned by business departments that lack the technical skills to effectively manage ERP security. In these scenarios, business owners should take steps to share ownership with IT functions, especially technical resources within their organization that are more accustomed to dealing with infrastructure or platform-level security. There is often a strong relationship between the strength of SAP security in organizations and the degree of partnership between business and IT.

A Ten Step Guide to Implementing SAP’s New Security Recommendations

On January 16, SAP issued a revamped version of the whitepaper Secure Configuration of SAP Netweaver Application Server using ABAP, which is rapidly becoming the de-facto standard for securing the technical components of SAP. According to SAP, the guidance provided in the whitepaper is intended to help customers protect ABAP systems against unauthorized access within the corporate network. In fact, many of the recommendations can also be used to protect SAP systems against remote attacks originating outside such a network. These attacks are targeted at the technical components of SAP Netweaver that are responsible for managing user authentication, authorization, encryption, passwords and system interfaces, as well as underlying databases and operating systems. Breaches in these components can enable attackers to take complete control of an SAP environment.

The following is a quick guide to help you comply with SAP’s recommendations.

1. Disable unnecessary network ports and services. In most cases, this means blocking all connections between end user networks and ABAP systems other than those required by the Dispatcher (port 32NN), Gateway (33NN), Message Server (36NN) and HTTPS (443NN). NN is a placeholder for your SAP instance number. Administrative access should only be allowed through secure protocols such as SSH and restricted to dedicated subnets or workstations through properly configured firewall rules.

2. Install the latest version of SAP GUI. This should be 7.10 or 7.20 with activated security rules configured with the ‘Customized’ setting and the ‘Ask’ default action.

3. Implement strong password policies, restrict access to password hashes in tables and activate the latest hashing algorithms. SAP does not specify the exact settings for password policy parameters but you should use frameworks such as the PCI DSS as a proxy. Refer to section 8.5 of the standard. Default passwords should be changed for standard users and the password hashing mechanism should be upgraded to the latest version available for your system. Wherever possible, downward-compatible hashes should be removed from the database.

4. Enable SNC and SSL. SAP client and server communication traffic is not cryptographically authenticated or encrypted. Therefore, data transmitted within SAP networks can be intercepted and modified through Man-In-The-Middle attacks. Secure Network Communication (SNC) should be used for mutual authentication and strong encryption. This can be performed natively if both servers and clients run on Windows. You will need to use a third party product to secure connections between heterogeneous environments such as AIX to Windows.

SNC will secure network communication using the SAP DIAG and RFC protocols. For Web-based communication, you should switch to HTTPS/ SSL and restrict access to the relevant cryptographic keys.

5. Restrict ICF services. Many of the services enabled by default in the Internet Communication Framework (ICF) are open to abuse and could enable unauthorized and malicious access to SAP systems and resources. At a very minimum, you should deactivate the dozen or so services mentioned by SAP in the white paper. This can be performed through transaction SICF.

6. Secure Remote Function Calls (RFC). Wherever possible, remove trust relationships between systems with differing security classifications and hardcoded user credentials in RFC destinations. The belief that RFC connections using SAP_ALL privileges is fine as long as the user type is not set to dialog is a myth. This represents a serious risk to the integrity of information in SAP systems.

7. Secure the SAP Gateway. The Gateway is used to manage RFC communications which support SAP interfaces such as BAPI, ALE and IDoc. Access Control Lists (ACL) should be created to prevent the registration of rogue or malicious RFC servers which can lead to the interruption of SAP services and compromise data during transit. You should also enable Gateway logging and disable remote access.

8. Secure the SAP Message Server. The Message Server is primarily a load balancer for SAP network communications. Similar to the Gateway, it has no default ACL which means it is open to the same type of attacks. You should filter access to the Message Server port using a firewall and create an ACL for all required interfaces.

9. Regularly patch SAP systems. Implement missing SAP Security Notes and patch systems at least once a month. Security Notes can be downloaded from the SAP Service Market Place.

10. Regularly monitor the SAP security configuration. Standard SAP services such as EarlyWatch (EWA) and the Computing Center Management System (CCMS) can be used to monitor some security-relevant configurations. However, they do not provide the same coverage as professional-grade security tools such as those used by Layer Seven Security. You can learn more about SAP security monitoring through vulnerability assessment here. To discover why vulnerability assessments should be an integral component of your SAP security framework, click here.

When do default passwords become a configuration error?

The answer is when your Legal department is managing the fallout after a data breach. The case in point is the Utah Department of Health which announced this week that over 280,000 records belonging to Medicaid and CHIP recipients were compromised after a breach last week believed to be perpetrated by a group in Eastern Europe (http://www.health.utah.gov/databreach).

The group exported 25,000 files containing personal information including social security numbers, belonging to hundred of thousands of individuals. According to the Department, the breach was caused by “a configuration error at the authentication level of a server’s multilayer security system.” This seems like a rather euphemistic way of saying the server had a default password that the attackers were able to exploit. The Department states that it has implemented ‘corrective measures’ which presumably includes changing the password. It has also offered free credit monitoring for those effected by the breach.

To learn how to manage default users and passwords in SAP systems, download our free white paper at http://layersevensecurity.com/SAP_security_white_papers.html.

Why you should immediately patch the recent DoS Vulnerability in AIX

IBM released an advisory in February for a Denial of Service (DoS) vulnerability in AIX versions 5.3, 6.1, and 7.1. The warning seems to have flown under the radar since so far, many companies running the effected AIX OS platforms for their SAP environments have yet to deploy the patch. The vulnerability relates to a flaw in ICMP packet handling. An ICMP echo reply with ID=1 can lead to a DoS. ICMP is part of the Internet Protocol Suite and can be used to relay query messages. Echo reply is a ping utility that can be executed remotely with no authentication and very little complexity. The vulnerability has a CVSS base score of 7.8 and exploitability sub-score of 10 which means it is rated as extremely dangerous. The relevant security update can be downloaded directly from IBM through ftp://aix.software.ibm.com/aix/efixes/security/icmp_fix.tar. Technical information is available at http://www-01.ibm.com/support/docview.wss?uid=isg1IV08255.

 

Microsoft Hack Exposed Credit Card Details

Earlier today, Microsoft issued a statement that declared that the financial information belonging to customers of its online store in India may have been compromised by the recent attack perpetrated by a Chinese group called the “Evil Shadow Team.”

It is widely believed that this information was stored in clear text in databases raided by the group. The Evil Shadow Team may also have breached the supposedly secure gateway handling the payment process. In an original statement issued shortly after the attack, Microsoft had claimed the group had only compromised login IDs, passwords and possibly shipping addresses. However, after further investigation, it appears that the damage was far worse. Two weeks after the attack, the online store is still down, suggesting there are serious issues with the site.

To learn how to secure SAP systems against similar attacks, read our whitepaper.

Netweaver Single Sign-On: Is it Worth the Risk?

SAP’s acquisition of SECUDE in 2011 is finally bearing fruit. Recently, SAP announced the launch of Netweaver Single Sign-On 1.0 which can be downloaded from the Service Marketplace. This is the latest addition to SAP’s identity and access management portfolio and is based on SECUDE’s Secure Login and Enterprise SSO solutions. It uses protocols such as Kerberos, X.509 and SAML to enable mutual authentication between not only SAP applications but between SAP and legacy systems. It also supports cross-company authentication between different domains. This is achieved through federated identity systems based on a choice of IDP or STS, which is used to issue and verify security tokens.

SSO aligns well with SAP’s ambition to ‘help companies run better’.  It does so by seamlessly integrating people, processes and technology without the inconvenience of multiple logons. It also lowers the Total Cost of Ownership (TCO) by reducing the burden on Helpdesks that spend an inordinate amount of time helping locked-out users reset their passwords. According to research performed by the META Group (now owned by Gartner) 20-50% of all support calls are caused by forgotten or expired passwords. The cost to manually reset passwords ranges from $15-30 per call, and on average, users call help desks with a password problem 4 times a year”. Forrester Research estimates the average cost is closer to $70. This should give SAP a leg up over the competition, not that it needs it, judging by the latest results.

For security folks, the case for SSO is less clear cut. While it enables companies to standardize and enforce stricter password policies to legacy systems, simplify administration and reduce the risk that users will write down credentials needed to logon to different systems, SSO has some serious drawbacks.

Firstly, implementing SSO is no picnic. Retrofitting legacy systems can be a nightmare. Secondly, since SSO only deals with authentication and not authorization, the administrative gains are minimal: somebody still has to setup privileges for every new user. Privileges are rarely synchronized between systems.

Thirdly, it creates a single point of attack. This is by far the most serious concern with SSO which delegates authentication to a single, central Identity and Access Management (IAM) system. IAMs are attractive targets for attackers, especially when they provide direct access to information-rich SAP systems. Attack vectors used to compromise SSO logins and passwords range from cross-site scripting, phishing to social engineering and have been successfully deployed against SSO schemes used by tech giants such as Google, Facebook and Twitter. A special mention should be given to Denial of Service (DoS) attacks. Note that SSO intensifies the damage caused by DoS against an IAM since it impacts every system relying upon the IAM for authentication.

Clearly, SSO is a double-edged sword. To realize the benefits, you have to manage the risks. This should include multi-factor authentication and hardening of all systems in the SSO environment. The latter should include regular patching, client-side security such as SNC encryption for SAP GUI traffic and host-level vulnerability assessments. You can learn more about SAP vulnerability management here.

SAP patches a session hijacking vulnerability in the Netweaver Portal

Imagine a system that provides a single, unified interface to all your SAP applications for not only everyone in your company but customers and suppliers. Imagine also that this system is web-based and uses single-sign-on. Congratulations, you’ve just envisioned the Netweaver Portal, the cornerstone of SAP’s strategy to integrate business information and processes and the fountain of much of the company’s recent success. Given its importance, you would think that any security vulnerability in the Portal would be quickly dealt with by SAP’s security engineers. Yet, if this is the case, why did it take SAP one and a half years to patch a vulnerability that left the Portal open to session hijacking?

Session hijacking is also known as session fixation or broken authentication and ranks consistently high in the OWASP Top Ten web application security risks. In fact, in the most recent survey, its rated as the third most prevalent and dangerous vulnerability in web applications. Hijacking occurs when attackers exploit weak functions in the application layer to assume the identities of legitimate users. Attackers usually target passwords, keys, session tokens and other authentication factors. Its not that difficult to find flaws in most applications since developing secure authentication and session management schemes for custom applications is no walk in the park. SAP applications are no different.

In July 2009, SAP was notified about a session fixation flaw in the J2EE engine that affected versions 6.4-7.2 of the Netweaver platform, which is essentially the technical layer of SAP systems. In the words of SAP itself, this flaw could be exploited to gain access to authenticated user sessions (SAP Note 1310561) through attack vectors such as MITM that provide hackers with access to the session IDs of SAP users which can then be used to logon to target SAP systems. The impact can be very high, especially when you consider that the Portal provides Web-based access to HR, financial, customer relationship management, product lifecycle management, and other critical applications (SAP Solution Brief).

The session hijacking vulnerability was eventually patched by SAP through the introduction of JSESSIONMARKID, a secure (HTTPS) cookie that automatically renews after successful logons. However, the shocker was that it took SAP 18 months to develop and release a patch for the vulnerability. That’s twice the length it took the company to rollout its new database, HANA, from “idea to completion” (Vishal Sikka, SAP AG Board member). Its possible that the existence of this vulnerability was well known within hacking communities long before the much anticipated fix was released by SAP. Disclosure guidelines issued by SAP urge security researchers not to publicize information about vulnerabilities until they are patched. Most researchers, rightfully so, choose to follow SAP’s request. However, given the severity of these and other vulnerabilities, customers shouldn’t accept such a long window for patch management. After all, if SAP can develop and release an entirely new database in a mere 9 months, surely it can fix a critical security flaw in its Portal just as quickly.

A Guide to Rootkits and Trojans in ABAP Programs

If you missed Ertunga Arsal’s presentation on SAP Rootkits and Trojans at the 27th Chaos Communication Congress, you can now watch the entire hour-long session below. Ertunga is an accomplished SAP security expert and an entertaining speaker if you appreciate dry, German humour. In this video, Ertunga demonstrates how attackers can use several paths to compromise weak SAP systems (usually development or test environments), infect clients that connect to the compromised systems and then eventually work their way up to production and even partner systems. These so-called˜Triple Penetration’ attacks can compromise entire SAP landscapes.

Ertunga also demonstrates how attackers can crack hashed SAP passwords and discusses problems with SSO. He makes a great comment about how SSO is really a convenience feature and does nothing to improve security and shows how attackers can create their own SSO certificates to logon to SAP using the IDs of users in the target system.

However, the highlight of the session is the discussion around SAP Rootkits and Trojans. Ertunga walks through several injection attacks that can be used to infect ABAP programs. Rootkits can be used to execute commands that, for example, automatically donate part of a company’s profit to charity (the so-called ‘Robin Hood’ worm) or publish salary information online. He points out that development activities should be tightly controlled and monitored, especially if you’re using third party developers with SAP_ALL rights. If your developers are internal, Ertunga warns against hiring developers from competitors since this can open the door to commercial espionage and sabotage.