Tag Archives: Remote Code Execution Vulnerability

Critical Wormable Vulnerability CVE-2019-0708 patched. Is the world a safer place now?

19 May 2019

Microsoft released (1) a patch for the critical Remote Code Execution vulnerability CVE-2019-0708 (2) in Remote Desktop Services on May 14th, 2019. The vulnerability is wormable. A malware that exploits the vulnerability can spread from vulnerable computer to vulnerable computer in a way WannaCry did in 2017. Fortunately, only Windows XP, Windows 2003 Server, Windows 7 and Windows 2008 Server are impacted.

How big is the problem?

A Shodan search shows that about 30% of the Windows 2008 server systems directly connected to the internet are impacted. The Windows 2003 problem is much larger although Microsoft stopped the extended support for this version in July 2015.

Table 1: CVE-2019-0708 Impacted Systems. Source: Shodan. Data generated: 5/19/2019 7:30 pm

How to mitigate?

Since CVE-2019-0708 is a remote code execution vulnerability patches or other mitigating measures should be applied directly.

Microsoft provided patches with the May 2019 patch set, even for Windows 2003 Server and Windows XP, to prevent similar effects to that of WannaCry on the global economy. As an immediate step, Microsoft recommends deactivating RDP access to the impacted systems.

Is the world a safer place now?

Far from it. A brief analysis shows that many of the impacted systems provide applications based on a WAMP technology stack (Windows, Apache, MySQL, PHP). And in many cases remote code execution vulnerabilities in Apache or PHP are not patched. With this, the overall security level remains as bad as before Microsoft released the patches.

Without vulnerability and application life cycle management such problems cannot be solved. Apache, MySQL and PHP can be operated on top of an outdated Windows OS, but critical vulnerabilities in these components must be patched directly to avoid a large financial impact in the worst case.

The Equifax data breach from 2017 is just one example. In this case an unpatched remote code execution vulnerability in the Apache Struts framework opened the door for the attackers. Equifax (3) estimates that it has spent $1.4 billion so far to recover from the breach.

Have a great week.


References

  1. MSRC Team. Prevent a worm by updating Remote Desktop Services (CVE-2019-0708) – MSRC [Internet]. 2019 [cited 2019 May 19]. Available from: https://blogs.technet.microsoft.com/msrc/2019/05/14/prevent-a-worm-by-updating-remote-desktop-services-cve-2019-0708/
  2. NIST NVD. NVD – CVE-2019-0708 [Internet]. 2019 [cited 2019 May 19]. Available from: https://nvd.nist.gov/vuln/detail/CVE-2019-0708
  3. Olenick D. Equifax data breach recovery costs pass $1 billion [Internet]. SC Media. 2019 [cited 2019 May 19]. Available from: https://www.scmagazine.com/home/security-news/data-breach/equifax-data-breach-recovery-costs-pass-1-billion/
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SpeakUp – Lateral movement made easy

10 March 2019

A remote command-injection vulnerability dubbed SpeakUp (CVE-2018-20062) (1) in the ThinkPHP development framework was widely reported in the news some weeks ago. Technically, SpeakUp is simply one more command-injection vulnerability with CVSS V3.0 base score Critical that results in full loss of integrity if exploited.

CVE-2018-20062 alike Vulnerabilities 2018

CVE-2018-20062 alike Vulnerabilities 2018

CVE-2018-20062-class vulnerabilities are quite rare. As of 10 March 2019 only 182 of the 16517 vulnerabilities published in 2018 belong to this class. Exploitation of any of these vulnerabilities results in full loss of integrity of the attacked system. In the worst case, the compromised system becomes the new base of operations for the attacker and allows him to compromise further systems.

Tara Seals provides a brief outline (2) on ThreatPost of the initial infection routine. For more details see the Checkpoint Research report (3) about SpeakUp.

Lateral movement in Linux-based networks places special challenges on the attacker. In general, vulnerabilities in applications must be used for propagation. SpeakUp uses an impressive arsenal of old vulnerabilities in application frameworks for propagation. Seals writes:

“To spread, SpeakUp’s propagation code exploits known vulnerabilities in six different Linux distributions, including JBoss Enterprise Application Platform security bypass vulnerabilities (CVE-2012-0874); a JBoss Seam Framework remote code execution (RCE) flaw (CVE-2010-1871); a JBoss AS 3/4/5/6 RCE exploit; a Oracle WebLogic wls-wsat Component Deserialization RCE (CVE-2017-10271); a vulnerability in the Oracle WebLogic Server component of Oracle Fusion Middleware (CVE-2018-2894); a Hadoop YARN ResourceManager command-execution exploit; and an Apache ActiveMQ Fileserver File Upload RCE vulnerability (CVE-2016-3088).”

The table below shows some details of the above mentioned vulnerabilities.

CVE

Application Framework

CVSS Base Score

Attack Vector

CVE-2012-0874

JBoss Enterprise Application Platform (EAP)

6.8 (CVSS v2.0)

V:N/AC:M/Au:N/C:P/I:P/A:P (CVSS v2.0)

CVE-2010-1871

JBoss Enterprise Application Platform (EAP)

6.8 (CVSS v2.0)

(AV:N/AC:M/Au:N/C:P/I:P/A:P) (CVSS v2.0)

CVE-2017-10271

Oracle WebLogic Server

7.5 (CVSS v3.0)

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (CVSS v3.0)

CVE-2018-2894

Oracle WebLogic Server

9.8 (CVSS v3.0)

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (CVSS v3.0)

CVE-2016-3088

Fileserver web application in Apache ActiveMQ

9.8 (CVSS v3.0)

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (CVSS v3.0)

Any of the listed vulnerabilities enables the attacker to create new operations bases. In the worst case, he can jump across network boundaries, e.g. from the DMZ into the company intranet or from the company intranet into the production network.

How to stop this kind of attacks?

From the tactical point of view, vulnerability management is the key to stop this kind of attacks as early as possible. CVE-2018-20062-class vulnerabilities and remote code or script execution vulnerabilities must be patched directly after they show up on the market. At least in the DMZ and on systems on both sides of network boundaries. This will prevent the attacker from lateral movement.

Vulnerability management relies on asset management. And on CI/CD across the entire application stack because without automated testing it is not possible to make sure that the application is still working after the patches have been applied.

From a strategic point of view, measures must be applied to enlarge the resilience of application systems against cyber attacks. This includes e.g. micro segmentation or Web Application Firewalls but also Linux native enhancements like AppArmor or SELinux.

And this holds for both, cloud and on-premise hosted applications.

Have a great week.


References

1. NIST NVD. NVD – CVE-2018-20062 [Internet]. 2018 [cited 2019 Feb 6]. Available from: https://nvd.nist.gov/vuln/detail/CVE-2018-20062

2. Seals T. SpeakUp Linux Backdoor Sets Up for Major Attack [Internet]. threatpost. 2019 [cited 2019 Feb 6]. Available from: https://threatpost.com/speakup-linux-backdoor/141431/

3. Check Point Research. SpeakUp: A New Undetected Backdoor Linux Trojan [Internet]. Check Point Research. 2019 [cited 2019 Feb 6]. Available from: https://research.checkpoint.com/speakup-a-new-undetected-backdoor-linux-trojan/


 

Adobe Flash zero day exploited in the wild. Remote code execution vulnerabilities are hacker’s favorites!

8 December 2018

On December 5th, 2018 Adobe published security bulletin APSB18-41[1] for critical vulnerability CVE-2018-15928 in the widely used Flash Player. Gigamon Applied Threat Research (ATR) reported the vulnerability on November 29th, 2018 to Adobe. They detected the issue some days before while analyzing a malicious word document that was uploaded to VirusTotal from a Ukrainian IP address. For a detailed analysis of the attack and the vulnerability see [2][3].

Successful exploitation of CVE-2018-15928 could lead to Arbitrary Code Execution in the context of the current user. Due to RedHat the CVSS3 Base Metrics is CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H with a CVSS3 Base Score of 8.8.

Zero days are not a rare phenomenon. Between 2013 and 2017[4] about 60% of the exploits were disclosed before the related CVE was published.

For about 20% of vulnerabilities in the NVD exploits are published in the exploit database[5]. Only about 1% of the vulnerabilities are exploited in the wild. Thus CVE-2018-15928 is a really rare event.

Remote code/script execution (RxE) vulnerabilities like CVE-2018-15928 represent about 20% of all vulnerabilities. 43% of the exploits published between 1988 and 2018 are related to RxE vulnerabilities.

Remote Code Execution Vulnerabilities. Data: 1988-2018

RxE Vulnerabilities. Data: 1988-2018

Exploits for Remote Code Execution Vulnerabilities. Data: 1988-2018

Exploits for RxE Vulnerabilities. Data: 1988-2018

About 5% of the RxE vulnerabilities are exploited in the wild.

This means, that RxE vulnerabilities are 5 times more often exploited in the wild then Non-RxE vulnerabilities. They are hacker’s favorites!

What does the mean for our vulnerability management strategy?

  • The remediation process must be started directly upon publication of an RxE vulnerability in the NVD or the disclosure of an exploit for an RxE in the exploit database.
  • In scope for the first remediation wave must be at least all systems facing the internet, e.g. workstations, servers in the DMZ or in public clouds.
  • Gathering intelligence about new vulnerabilities from a plethora of publicly available sources (OSINT) is a time-consuming task. A threat intelligence service can speed-up information gathering and reduces the workload of your IT security staff.
  • In addition, since remediation takes some time, it makes sense to invest in means for enhancing the resilience of application systems.

Expect the worst and be prepared. Or, to echo Hamlet:

To be, or not to be, that is the question:
Whether ’tis nobler in the mind to suffer
The slings and arrows of outrageous fortune,
Or to take arms against a sea of troubles,
And by opposing, end them? To die: to sleep;

Have a good weekend.


  1. Adobe. Security updates available for Flash Player | APSB18-42 [Internet]. 2018 [cited 2018 Dec 8]. Available from: https://helpx.adobe.com/security/products/flash-player/apsb18-42.html

  2. Gigamon Threat Research Team. Adobe Flash Zero-Day Exploited In the Wild [Internet]. Gigamon ATR Blog. 2018 [cited 2018 Dec 8]. Available from: https://atr-blog.gigamon.com/2018/12/05/adobe-flash-zero-day-exploited-in-the-wild/

  3. Qihoo 360 Advanced Threat Response Team. Operation Poison Needles – APT Group Attacked the Polyclinic of the Presidential Administration of Russia, Exploiting a Zero-day [Internet]. 2018 [cited 2018 Dec 8]. Available from: http://blogs.360.cn/post/PoisonNeedles_CVE-2018-15982_EN.html

  4. Jochem K. About 60% of exploits are published before the CVE. What does this mean for your cyber security strategy? [Internet]. IT Security Matters. 2018 [cited 2018 Dec 8]. Available from: https://klausjochem.me/2018/11/04/about-60-of-exploits-are-published-before-the-cve-what-does-this-mean-for-your-cyber-security-strategy/

  5. Offensive Security. Offensive Security’s Exploit Database Archive [Internet]. Exploit Database. [cited 2018 Nov 4]. Available from: https://www.exploit-db.com/

To patch or not to patch this is not the question – New Remote Code Execution Vulnerability in Drupal CMS

21 October 2018

Lindsey O’Donnell’s report “Two Critical RCE Bugs Patched in Drupal 7 and 8” [1] published yesterday on Threatpost gives website operators every reason to enter panic mode.

The vulnerabilities are not published in the NIST NVD yet, but Drupal released two security advisories [2] [3] with details.

Why panic? In the past 16 years 177 vulnerabilities [4] related to Drupal were published. That sounds like a lot but consider that 1,075,609 websites were powered with Drupal core in October 2018 [5].

Fortunately, only 13 exploits were published since 2002. On 29 March 2018 the remote code execution vulnerability CVE-2018-7600 (Drupalgeddon2) was published. Within 20 days after publication three exploits were available. Thousands of sites were compromised in the aftermath.

CVE-2018-7602 (Drupalgeddon3) was published on 19 July 2018. In this case exploits were available 81 and 86 days before the CVE was published.

Drupal Exploits since 2010

Table: Drupal Exploits since 2010. Click to enlarge.

The table above shows the vulnerabilities with published exploits for the Drupal CMS since 2010. Negative values in column Number of days exploit published after CVE published indicate that the exploit was published before the CVE was published. These are the magic zero-day exploits, the worst-case scenario for website operators because a warning time does not exist.

Except of the green highlighted exploit all exploits were used in the wild, means, they were used in attacks. In addition, except of the green highlighted exploit all CVE were remote code execution or injection vulnerabilities.

For the newly published remote code execution vulnerabilities we can expect

  • that exploits will be published with a probability of about 7% and
  • that if exploits are published, they will be published before or at the day the CVE is published.

With this, website operators must directly patch once they become aware of a new remote code execution vulnerability.

In addition, I would recommend to take additional preventive measures, e.g. to implement a Web Application Firewall or a Host based Intrusion Detection/Prevention System to make the installation more resilient against new vulnerabilities. If the website is operated on Linux it makes sense to activate  AppArmor [6].

Have a great week.


  1. O’Donnell L. Two Critical RCE Bugs Patched in Drupal 7 and 8 [Internet]. Threatpost | The first stop for security news. 2018 [cited 2018 Oct 20]. Available from: https://threatpost.com/two-critical-rce-bugs-patched-in-drupal-7-and-8/138468/
  2. Drupal ST. Drupal Core – Multiple Vulnerabilities – SA-CORE-2018-006 [Internet]. Drupal.org. 2018 [cited 2018 Oct 20]. Available from: https://www.drupal.org/sa-core-2018-006
  3. 3.Drupal ST. Mime Mail – Critical – Remote Code Execution – SA-CONTRIB-2018-068 [Internet]. Drupal.org. 2018 [cited 2018 Oct 20]. Available from: https://www.drupal.org/sa-contrib-2018-068
  4. CVE Details. Drupal Drupal : CVE security vulnerabilities, versions and detailed reports [Internet]. CVE Details. The ultimate security vulnerability datasource. 2018 [cited 2018 Oct 21]. Available from: https://www.cvedetails.com/product/2387/Drupal-Drupal.html?vendor_id=1367 
  5. Drupal.org. Usage statistics for Drupal core | Drupal.org [Internet]. 2018 [cited 2018 Oct 21]. Available from: https://www.drupal.org/project/usage/drupal
  6. theMiddle. AppArmor: Say Goodbye to Remote Command Execution. [Internet]. Secjuice.com. 2018 [cited 2018 Oct 21]. Available from: https://www.secjuice.com/apparmor-say-goodbye-to-remote-command-execution/

Digital Carelessness – a disease without a chance of cure

12 August 2018

Two messages this week showed that there is no cure in sight for the fatal disease called digital carelessness.

ONE: Two remote code execution (RCE) vulnerabilities found in certain HP Inkjet printers (1).

CVE-2018-5924: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVE-2018-5925: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

This sort of vulnerabilities is particularly popular in the cyber crime scene because they are network exploitable (Attack Vector AV:Network), attack complexity is low (AC:L), no privileges required (PR:None) and no user interaction is required (Ui:None).

Under normal conditions, Inkjet printers are operated inside the company network. Thus there is no need to enter into panic mode because the vulnerability can not be exploited from the internet.

Unfortunately, some HP Inkjet printers are, for whatever reason, accessible from the internet. A Shodan search reveals that 539 HP DesignJet printers are directly connected to the internet. One of the vulnerable printer models is the HP DesignJet T520 24-in ePrinter, Product number CQ890A, Firmware version 1829B. For a complete list of the affected printers please see the HP Security Bulletin HPSBHF03589 (2).

HP DesignJet T520 Map

HP DesignJet T520 Map. Click to enlarge.

As of today, 79 printers of this type are directly attached to the internet. Some of them are ready for printing and with this prone to CVE-2018-5924 or CVE-2018-5925 because the HP JetDirect Line Printer Daemon port 515 is open.

But why should an attacker exploit these RCE vulnerabilities if he can hijack the printer because basic security is not configured?

HP advised its customers to update the firmware of the affected printers as soon as possible. This is the best opportunity

  • to configure basis security,
  • to eliminate the http protocol, and
  • to close unnecessary open ports.

TWO: TSMC Chip Maker Blames WannaCry Malware for Production Halt

Taiwan Semiconductor Manufacturing Company (TSMC), the world’s largest makers of semiconductors and processors, was hit by a variant of the WannaCry ransomware last week. According to TSMC, its computer systems were not directly attacked, but instead, were exposed to the malware when a supplier installed corrupted software without a virus scan.

“We are surprised and shocked,” TSMC CEO C.C. Wei said, “We have installed tens of thousands of tools before, and this is the first time this happened. (3)

It doesn’t matter how often installations went well in the past. It’s always the next installation that counts.

Have a good week.


  1. Zorz Z. HP plugs critical RCE flaws in InkJet printers [Internet]. Help Net Security. 2018 [cited 2018 Aug 6]. Available from: https://www.helpnetsecurity.com/2018/08/06/hp-inkjet-printer-vulnerabilities/
  2. HP Customer Support. HPSBHF03589 rev. 2 – HP Ink Printers Remote Code Execution. 2018 [cited 2018 Aug 6]. Available from: https://support.hp.com/us-en/document/c06097712
  3. Wu D. iPhone Chipmaker Blames WannaCry Variant for Plant Closures. Bloomberg.com [Internet]. 2018 Aug 6 [cited 2018 Aug 12]; Available from: https://www.bloomberg.com/news/articles/2018-08-06/iphone-chipmaker-blames-wannacry-variant-for-plant-closures

Blockchain unchained?

3 June 2018

Blockchain technology is a digital platform for applications where seamless traceability and full transparency is required.

For example, in pharmaceutical industry blockchain could give full traceability of drugs across the entire supply chain up to the patients.

Another interesting application is mobile voting. From the Brookings publication “How blockchain could improve election transparency” (1) on the use of blockchain for internet voting in the West Virginia primaries in May this year we learn that “all data of the election process can be recorded on a publicly verifiable ledger while maintaining the anonymity of voters, with results available instantly”.

This sounds very promising.

Blockchain Grid

Picture By Davidstankiewicz, for details see below (5)

Unfortunately, every software has bugs. On May 28th, 2018 Swati Khandelwal reported in “The Hacker News” about a remote code execution (RCE) vulnerability in the blockchain-based EOS smart contract system (2).

If an attacker exploits this RCE he could destroy the integrity of the entire system:

“Since the super node system can be controlled, the researchers said the attackers can “do whatever they want,” including, controlling the virtual currency transactions, and acquiring other financial and privacy data in the EOS network participating node systems, such as an exchange Digital currency, the user’s key stored in the wallet, key user profiles, privacy data, and much more.”

Although it is not clear whether the voting system used in West Virginia is based on the Blockchain 3.0 platform there is urgent need for action. EOSIO set up a bug bounty program (3) to improve their code. But should we rely on bug bounty programs for such important issues like elections or patient safety?

From the Qihoo 360 security researchers report (4) we learn that the vulnerability is created by “a buffer out-of-bounds write” error. This means that this vulnerability could have been avoided by performing a static code analysis prior to release.

The big question is: How many errors of this type are still included in the blockchain infrastructure? A bug bounty program is a good approach to improve security, a static code analysis is indispensable in my view. In particular when the outcome of an election can be influenced or patient safety is endangered.

Have a great week.


References

1. Desouza KC, Somvanshi KK. How blockchain could improve election transparency [Internet]. Brookings. 2018 [cited 2018 Jun 1]. Available from: https://www.brookings.edu/blog/techtank/2018/05/30/how-blockchain-could-improve-election-transparency/

2. Khandelwal S. Critical RCE Flaw Discovered in Blockchain-Based EOS Smart Contract System [Internet]. The Hacker News. 2018 [cited 2018 Jun 1]. Available from: https://thehackernews.com/2018/05/eos-blockchain-smart-contract.html

3. eosio. Calling all Devs: The EOSIO Bug Bounty Program is Live [Internet]. Medium. 2018 [cited 2018 Jun 3]. Available from: https://medium.com/eosio/calling-all-devs-the-eosio-bug-bounty-program-is-live-7219c625a444

4. Chen Y, Peng Z. EOS Node Remote Code Execution Vulnerability — EOS WASM Contract Function Table Array Out of Bounds – 奇虎360技术博客 [Internet]. 2018 [cited 2018 Jun 1]. Available from: http://blogs.360.cn/blog/eos-node-remote-code-execution-vulnerability/

Picture Credits

5. By Davidstankiewicz [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)%5D, from Wikimedia Commons

Some thoughts on “Identity is the new perimeter”

28 January 2018

With the increasing adoption of cloud services, the traditional perimeter security approach becomes less and less effective. The on-premise security layer, which protects users against cyber-attacks, is just no longer existent if users have direct access to a company’s cloud services from any location, at any time and, in the best case, from any device.

The four “A”s, Authentication, Authorization, Administration and Audit, become more and more important in a [hybrid] cloud based working environment.

“When identity and access management (IAM) works well, it means the right people have the right access to the right resources when they need them with appropriate governance in place from wherever the data or application is needed.” [1]

The magic word is “right”: With IAM we control the access of well-known groups of people to well-known resources. Unfortunately, cyber attackers do often not belong to these groups.

NIST NVD Statistics: Privileges Required

From the NIST NVD we learn, that 67% of the vulnerabilities published in 2017 need no privileges for exploitation.

Privileges None means: “The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.” [2]

This holds e.g. for remote code execution (RCE) vulnerabilities. An RCE allows an attacker to get full control of the victim’s computer or service, in the worst case with administrative privileges. With this, the entire new perimeter is bypassed. For an RCE example see CVE-2017-11459. [3]

Identity becomes an important part of a new perimeter but can never replace the perimeter.

NIST NVD 2017 Statistics: User Interaction Required

The NIST NVD data give another important insight for shaping a company’s security strategy: In 41% (5958) of 14647 vulnerabilities the user must interact with the attacker for their exploitation.

This means that well-made user awareness training can prevent lots of cyber-attacks.

Have a great week.


[1] AusCERT 2017 – Identity is the new perimeter
Anthony Caruana, 05/30/2017, CSO Online
https://www.cso.com.au/article/619970/auscert-2017-identity-new-perimeter/
Last seen: 01/28/2018

[2] Common Vulnerability Scoring System v3.0: Specification Document
https://www.first.org/cvss/specification-document
Last seen: 01/28/2018

[3] CVE-2017-11459
https://nvd.nist.gov/vuln/detail/CVE-2017-11459
Last seen: 01/28/2018