Monthly Archives: June 2019

IoT, Potential Risk of CVE

Vulnerability might jeopardize IoT world – CVE-2019-10160 Python Security Regression Unicode Encoding Vulnerability (Jun 2019)

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Preface: IoT device similar a delivery arm of robotic concept. They are the python language heavy duty users.

Python language married with IoT devices – For IoT, there has been a variant of python called Micropython , that lets you program for IoT in Python. Additionally, developer can use Raspberry Pi to program your IoT applications in Python.

Vulnerability details: A vulnerability in the the urllib.parse.urlsplit and urllib.parse.urlparse components of Python could allow an unauthenticated, remote attacker to obtain sensitive information from a targeted system.

Synopsis: Python Web application (Web Frameworks for Python) which accepting Unicode URL will be converted to IDNA (Punycode) or ASCII for processing. This conversion will decompose certain Unicode characters that can affect the netloc part of your URL, potentially resulting in requests being sent to an unexpected host.

Remark: Parse a URL into six components, returning a 6-item named tuple. This corresponds to the general structure of a URL: scheme://netloc/path;parameters?query#fragment.

Remedy: Python has released a patch at the following link – https://github.com/python/cpython/commit/fd1771dbdd28709716bd531580c40ae5ed814468

2019, cyber security incident news highlight, Potential Risk of CVE

It will jeopardizing 400,000 Linux system in the world – Exim Releases Security Patches (alert issued in Jun 2019)

Preface: Exim is growing in popularity because it is open source.

Background:It’s the default mail transport agent installed on some Linux systems.It contain feature likes:
Lookups in LDAP servers, MySQL and PostgreSQL databases, and NIS or NIS+ services.

Vulnerability details: The vulnerability was patched in Exim 4.92, released on February 10, 2019. The vulnerable code is in “deliver_message()”. A vulnerability exists because the email address in the deliver_message() function in /src/deliver.c is not fully validated. So local attackers simply send emails to “${run{…}}@localhost”. Since “localhost” is a local domain of Exim) and execute as root (system privileges).

Remark: Deliver_drop_privilege is set to false by default.

Attack synopsis: If the “verify = recipient” ACL is manually deleted then remote attack will be occurred. Attacker can reuse our local-exploitation method with an RCPT TO “xxx+${run{…}} @ localhost”. Where “xxx” is the name of the local user .

For official details, please click on the link – https://www.exim.org/static/doc/security/CVE-2019-10149.txt

Potential Risk of CVE

CVE-2019-3567 osquery design flaw – unintended create hidden place for malware Jun 2019

Preface: Need to know what processes are running on a given machine? A servers current CPU temperature? Verify a hard drive is encrypted? OSQUERY can do, even though security monitoring.

Technical background: osquery is a tool that exposes an operating system as a high-performance relational database.The design founded by Facebook. It enables developers to write SQL-based queries that explore operating system data includes the following:

  • Running processes
  • Loaded kernel modules
  • Open network connections
  • Browser plugins
  • Hardware events
  • File hashes

Vulnerability detail: Osquery running on windows or Linux system requires the daemon configured to be a system service. Meanwhile, this operation will make service daemon receive the system privileges. The design feature of osquery unintended let attacker has a way pass the file to a hard link parent folder. So it is similar to create a hidden area for malware. Under such circumstances the malware payload can be operate under SYSTEM permissions. The official announcement is as follows: https://www.facebook.com/security/advisories/cve-2019-3567

Potential Risk of CVE

CVE-2019-12243 Istio improper internet access control vulnerability (Jun 2019)

Preface: Independently deployable is the strongest feature of microservices. Docker is one of the technology vendor keen to develop the microservice.

What is Istio? An open platform to connect, manage, and secure microservices. Istio is easy to deploy. User merely install a proxy (side-car proxy) and complete the configuration.

Vulnerability details: The vulnerability was impacting the TCP Authorization feature. A vulnerability in Istio could allow an unauthenticated, adjacent attacker to gain unauthorized access to a targeted system. Per vendor announcement, a self diagnose can find whether you are vulnerable of this bug. For details, please refer to the following.

Check the status of policy enforcement for your mesh with the following command: 

$ kubectl -n istio-system get cm istio -o jsonpath="{@.data.mesh}" | grep disablePolicyChecks

If the output shows that disablePolicyChecks is set to true, it will not be affected by this vulnerability.

Vendor released software updates at the following link: https://istio.io/about/notes/1.1.7/

Potential Risk of CVE

It looks very vague – Oracle Vulnerability CVE-2019-2517 (Jun 2019)

Preface: Every time you review Oracle security advisory. Your feeling is vague since no details will be provided!

Vulnerability details: A vulnerability in the Core RDBMS component of Oracle Database Server could allow an authenticated, remote attacker with high privileges to compromise a targeted system completely.

More details: The vulnerability resides in the Java Virtual Machine component of the Oracle Database Server and does not require user interaction. The vulnerability allows low-privileged attackers that have Create Session privilege with network access via Oracle Net to compromise the Java VM component.

How to identify your JVM for Oracle:

select * from all_registry_banners;

Impact: Since the vulnerability happen on JVM. Therefore successful exploit could allow the attacker to compromise the system completely.

Affected products: Oracle Database Server 12c12.2 (.0.1), Oracle Database Server 18cRelease Update 6 (18.6) (Base)

Remedy: Oracle released software updates at the following link – https://www.oracle.com/downloads/index.html

Network (Protocol, Topology & Standard)

Configure a strong PSK to avoid wireless offline cryptographic attack

Preface: Maybe people won’t use WPA because it’s not safe. However, WPA2 can also collect PSK through tools.

Technical details:

WPA and WPA2 offline attack technique are well known today. For instance, penetration test conduct the WiFi penetration test will relies on tool (Aircrack-NG). As a matter of fact, the attacker first obtains a man-in-the-middle (MitM) position between the victim and the real Wi-Fi network. However it does not enable the attacker to decrypt packets! One of the way use a password recovery tool work with “wordlist”. The mechanism is read line by line from a textfile (aka “dictionary” or “wordlist”) and try each line to find out the password.

Reference: The dictionary pass-phrase attack is one of the popular attacks on WPA2-PSK. Since PSK will be the main key to protect WLAN, the attacker will try to guess the pass-phrase used to generate PSK. This can be done by capturing the initial WPA2-PSK handshaking between a legitimate wireless client and the AP.

Remedy: Sounds like not difficult to crack. In our world, IoT devices do not use 802.1x for authentication. What can we do?

If not possible change to 802.1x, configure a strong PSK with a minimum length of 19 characters or more.

2019, cyber security incident news highlight

Did you have trouble accessing internet on Sat (8th Jun 2019 GMT+8)

Synopsis: The users were temporarily unable to reach adjacent countries internet web sites for short period of time (less than 1 – 3 minutes) due to an issue of Internet BGP backbone.

Description: On Sat, I was surprise that some internet web site looks unstable. It is not only happens on a single web site.

What do you think about or do you aware?
There are likely to be similar problems that you can find below:

  1. The ABC ISP (AS __xx) configured a static route 66.220.144.0/24 pointing to null in order to block Facebook access for ABC ISP customers. However, the ISP started to announce the prefix 66.220.144.0/20 towards its upstream provider CDEF (AS xxxx) that propagated the announcement to its peers. Meanwhile Facebook (AS32934) that had been announcing prefix 66.220.144.0/20 so far, started to fight back. Facebook began to announce more specific prefix 66.220.144.0/24. They kept announcing 66.220.145.0/24, however the service would still not be available for a large part of Facebook users. Those were the users whose traffic took a path towards ABC ISP (AS__xx), thus it could not reach Facebook. The traffic was being backhauled by a static route configured on ABC (AS__xx) edge router.
  2. Bogus AS Path
Potential Risk of CVE

We may ignore the vulnerabilities that happened in the past! Jun 2019

Preface: The virtual table is created in the same SQLite database in wich the Core Data content resides. To keep this table as light as possible only object properties relevant to the search query are inserted.

Vulnerability details: A vulnerability in the rtreenode() function of SQLite3 could allow an unauthenticated, remote attacker to access sensitive information .

Bug Fixed – When opening an existing rtree, determine the node size by inspecting the root node of the r-tree structure (instead of assuming it is a function of the page-size). SQLite has released a software update at the following link: https://www.sqlite.org/download.html

Potential Risk of CVE

CVE-2019-10981 AVEVA Security Advisory LFSEC00000136 (May 2019)

Preface: In the Ukraine hack, the utilities not only lost their visibility but also ceded control of their networks to remote attackers later linked to APT Group (Dec 2015).

About AVEVA : AVEVA Group plc is a British multinational information technology company headquartered in Cambridge, United Kingdom. It provides engineering and industrial software. Schneider Electric is now the largest shareholder with a 60% ownership interest.

Vulnerability details:

In Vijeo Citect 7.30 and 7.40 and CitectSCADA 7.30 and 7.40 versions, it could allow a malicious entity to obtain the Citect User Credentials because Citect User Credentials in memory are stored in clear text.
Remark: If the client deploy above solution and does not integrate workstation with internet function. The cyber security risk will be retained similar vendor opinion. It is a medium risk. Properly require adjust the rating if client workstation has internet web browsing function.

The official announcement is as follows: https://sw.aveva.com/hubfs/assets-2018/pdf/security-bulletin/SecurityAdvisory_LFSec136.pdf

Potential Risk of CVE, Under our observation

Microsoft Windows RDP Network Level Authentication can bypass the Windows lock screen – Jun 2019

Vulnerability Note VU#576688
Original Release Date: 2019-06-04 | Last Revised: 2019-06-04

Preface: The more the power you have, the greater the risk is being infected.

Synopsis: Microsoft Windows RDP Network Level Authentication can allow an attacker to bypass the lock screen on remote sessions.

My observation: Observing that Microsoft re-engineering the RDP with create a channel with MS_T120 and Index 31.
But vulnerability occurs when someone send data to the system’s MS_T120 channel and reference the closed channel again.

Interim remediation step:

  • RDP is disabled if not needed.
  • SIEM firing rule – client requests with “MST-T120′ on any channel other than 31

Reference: https://kb.cert.org/vuls/id/576688/