
Guidance on Defending Against Video Teleconferencing (VTC) Hijacking and Zoom-bombing
The Federal Bureau of Investigation (FBI) has released an article on defending against video-teleconferencing (VTC) hijacking (referred to as “Zoom-bombing” when attacks are to the Zoom VTC platform).
Read More
Advisory On RDP Brute Force Attacks
A way for employees to access corporate devices is by using Remote Desktop Protocol (RDP). Remote Desktop is a remote management tool which allows you to connect to any computer and take over the desktop.
Read More
Alert Regarding Vulnerability (CVE-2019-19781) in Citrix Products
CERT-GH confirmed that information including Proof-of-Concept code about a
vulnerability
(CVE-2019-19781) in Citrix Application Delivery Controller and Citrix Gateway
has been
made public. A remote attacker leveraging this vulnerability may execute
arbitrary code.

Avoid Phishing Scams
Scammers use email or text messages to trick you into giving them your personal information. They may try to steal your passwords, account numbers, or Social Security numbers.
Read More
Website Defacement
Website defacement is an attack on a website that changes the visual appearance of the site or webpage. It is similar to drawing graffiti on a wall, only it happens virtually as a kind of electronic graffiti and is a form of vandalism.
Read More
How to identify malware on your phone
When a smartphone is infected with malware, it can cause several problems, including allowing hackers to steal private information from the victim.
Read MoreAlert Regarding Vulnerability (CVE-2019-19781) in Citrix Products
CERT-GH confirmed that information including Proof-of-Concept code
about a
vulnerability (CVE-2019-19781) in Citrix Application Delivery Controller and Citrix
Gateway has
been made public. A remote attacker leveraging this vulnerability may execute arbitrary
code.
On January 12, 2020, Bad Packets released information about scanning activities that
appeared to
be leveraging the vulnerability.
Products affected by these vulnerabilities include:
- Citrix ADC and Citrix Gateway version 13.0
- Citrix ADC and NetScaler Gateway version 12.1
- Citrix ADC and NetScaler Gateway version 12.0
- Citrix ADC and NetScaler Gateway version 11.1
- Citrix NetScaler ADC and NetScaler Gateway version 10.5
- Citrix SD-WAN WANOP software and appliance model 4000
- Citrix SD-WAN WANOP software and appliance model 4100
- Citrix SD-WAN WANOP software and appliance model 5000
- Citrix SD-WAN WANOP software and appliance model 5100
The method of confirming whether this vulnerability is exploited is as follows;
- Check if there is any access to the device from a suspicious IP
address.
- The log of HTTP traffic to the device is recorded in httpaccess.log and httperror.log
- Check whether traffic that exploits the vulnerability is recorded in
the
device
log.
- If the Proof-of-Concept code that exploits this
vulnerability is
executed, traffic including the following string is recorded
in the
device.
/vpns/
/vpn/../vpns/cfg/smb.conf
/vpn/../vpns/portal/scripts/newbm.pl
/vpn/../vpns/portal/backdoor.xml
/vpns/portal/scripts/newbm.pl
- If the Proof-of-Concept code that exploits this
vulnerability is
executed, traffic including the following string is recorded
in the
device.
- Check the files under the following directory on the device.
- If there is a recently created unknown xml file, the file is
a
malicious file
created by an attacker, it is possible that an attack has
been
already conducted to compromise the device.
/var/tmp/netscaler/portal/templates
/netscaler/portal/templates
- If there is a recently created unknown xml file, the file is
a
malicious file
created by an attacker, it is possible that an attack has
been
already conducted to compromise the device.
-
Check device processes and corn jobs
- Execute commands on the device to check if there is any process or corn job running by the user "nobody".
- If this vulnerability is exploited, processes are executed by a user named "nobody". If such processes are running, it is possible that an attack has been already conducted to compromise the device.
You can also Download and Run the citrix-vuln-checker.py script in your terminal to check if your CITRIX SERVER is vulnerable to the CVE-2019-19781 https://github.com/inveteck/citrix-vuln-checker
References
Inveteck Global https://github.com/inveteck/citrix-vuln-checker
As of January 17, 2020, Citrix has not provided solution for this
vulnerability.
Please consider applying "V. Mitigation" or discontinuing the use of the
products.
Also, Citrix is planning to provide versions addressing the
vulnerability on the
following dates.
January 24, 2020
- Citrix NetScaler ADC and NetScaler Gateway version 10.5
On January 24, Citrix released the version 10.5 of Citrix NetScaler ADC
and
NetScaler Gateway that addresses this vulnerability. Since attacks
leveraging
the vulnerability are still being observed, we would recommend to apply
solution
and check whether system has been compromised as soon as possible.
Please consider to apply the following mitigation.
- Restrict unnecessary traffic by firewall, etc
- Apply workarounds provided by Citrix
Citrix Systems
Mitigation Steps for CVE-2019-19781
https://support.citrix.com/article/CTX267679
According to Citrix information, Citrix ADC version 12.1 builds
51.16,51.19 and
builds prior to 50.31 have bugs and mitigation settings are not applied.
It is
recommended to update to a build that is not affected by this bug in
order to
properly apply the mitigation.
Guidance on Defending Against Video Teleconferencing (VTC) Hijacking and Zoom-bombing
The Federal Bureau of Investigation (FBI) has released an article on
defending against video-teleconferencing (VTC) hijacking (referred to as “Zoom-bombing”
when attacks are to the Zoom VTC platform). Many organizations and individuals are
increasingly dependent on VTC platforms, such as Zoom and Microsoft Teams, to stay
connected during the Coronavirus Disease 2019 (COVID-19) pandemic. The FBI has released
this guidance in response to an increase in reports of VTC hijacking.
The National Cyber Security Centre encourages users and administrators to review the FBI
Article (Click Here) as well as the following steps to improve VTC cybersecurity:
- Ensure meetings are private, either by requiring a password for entry or controlling guest access from a waiting room.
- Consider security requirements when selecting vendors. For example, if end-to-end encryption is necessary, does the vendor offer it?
- Ensure VTC software is up to date. See Understanding Patches and Software Updates.
Microsoft https://www.us-cert.gov/ncas/current-activity/2020/04/02/fbi-releases-guidance-defending-against-vtc-hijacking-and-zoom
How to identify malware on your phone
When a smartphone is infected with malware, it can cause several problems, including
allowing
hackers to steal private information from the victim.
Understanding how to check if a phone has a virus is an important step for any
smartphone owner.
There are several signs that may indicate the presence of a virus on the device and if
these
signs are identified, it is critical to take appropriate action such as using a reliable
anti-virus.
There are many security threats that smartphone users have to be aware of, including the
latest
DNS-hijacking that hackers now perform. Failure to check for a virus on the phone when
infected
can lead to several problems, including ransomware, cryptojacking and stealing of
confidential
data. Additionally, there are malware that may cause problems with the smartphone’s
physical
function as well.
- Sudden Increase in Data Usage
One of the first signs when looking at how to find out if your phone has a virus would be a sudden increase in data usage. Even though some applications and games on a smartphone can be heavy on data, when there is a sudden increase in the amount of data used without any obvious reasons, it may be a sign that the phone has been infected with a virus especially malware like ADB.miner known for mining Monero coins on Android phones and Smart TVs. - Battery is Draining Faster Than Usual
Another common sign that tends to signal an infection on a smartphone is the battery that suddenly starts to drain faster than usual. While this can sometimes be a sign that the battery is damaged, there are various kinds of viruses that may also cause a smartphone battery to drain quickly. -
Poor performance of smartphone
Some of the more recent smartphones on the market tend to be equipped with powerful processors and enough RAM to easily deal with the latest technologies used in apps and games. When a smartphone that has this type of technology fitted starts to lack performance suddenly, it may also be a sign that the device is infected with a virus.
The poor performance will sometimes only be noticeable when launching a game that requires a powerful CPU and GPU. In other cases, a virus may cause the general performance of a mobile device to lack as well – even when performing simple tasks, such as making a call or reading an SMS. -
Smartphone Starts to Overheat
In addition to finding that the smartphone is performing poorly, another sign that it is infected with a malware like HiddenMiner would be overheating. This is an uncommon issue in most smartphones; thus, when there is a problem with overheating, a virus scan may uncover such malware on the phone. - Unfamiliar Apps Start to Show Up on The Device
A virus that infects a smartphone may sometimes cause unfamiliar apps to install automatically. Thus, when there are apps showing up on the phone without the user’s permission, then this may be yet another sign that the device has been infected with a virus. - Wi-Fi And Mobile Data Switches on Automatically
When looking to learn how to find out if your phone has been infected with malware, a person should be wary of their mobile data and Wi-Fi switches. Since viruses will often send and receive data through the internet, the infection may cause data to be turned on after the user has disabled either their mobile data or their Wi-Fi connection. - Pop-Up Ads
Another annoying, but an obvious sign of a virus on a mobile device would be the sudden appearance of pop-up ads. These will usually show up even after the user has left an application and remains on the homepage of their phone. The pop-up ads will sometimes show inappropriate advertisements, or lead the user to mobile applications on smartphone app stores.
Malware can affect both computers and mobile devices. When a smartphone is affected, it can cause personal data to be leaked to hackers. In these cases, there are several issues that come to mind, including confidential details that might be stored on the smartphone. Those who suspect they might be infected should learn how to find out if their phone has a virus. This can help take action to remove the virus and protect sensitive data.
Website Defacement
CERT-GH of the National Cyber Security Centre provides the following advisory.
This is to advise all Web host users, managers and business owners in Ghana of cases of
website defacement identified by CERT-GH
Website defacement is an attack on a website that changes the visual appearance of the site or webpage. It is similar to drawing graffiti, only it happens virtually as a kind of electronic graffiti and is a form of vandalism. These are typically the work of hackers, who break into a web server and replace the content the hosted website with one of their own. Attackers have different motivations when they deface a website. Political motivation is one, which is often used to spread messages by “cyber protesters” or hacktivists. Other attackers may choose to deface a website for fun – to mock site owners by finding website vulnerabilities and exploiting these to deface a website. In both cases, website owners face damages to their business and reputation once their sites are defaced.
Consequences of website defacement vary. Here are some consequences an organization may face after its website has been attacked.
- Potential Data breach: Due to the noticeable nature of web defacement, some hackers use them as a form of diversion. With everyone’s attention focused on the defacement, these hackers can then carry out more sinister activities without getting detected immediately. For instance, they could steal sensitive information, install malware, and perform privilege escalation or carry out other nefarious acts.
- Losing Customers: Visitors may be redirected to sites teeming with malicious code. They might be prompted to download malware onto their system or it downloads itself, undetected. In such cases, your regular and new visitors may be concerned about visiting your page in the future and you can potentially lose customers.
- Impact on PageRank and Traffic: Search engines rank your website according to a number of factors. A higher ranking website comes up first in the results of a search query. If your defaced website is flagged or identified as causing harm to its users, a search engine such as Google might add you to its blacklist. This means that you can lose up to 95% of website traffic that could be gained from Google search results.
- Effect on Brand Image: Internet users worry about safety during their online experiences. If they notice you have failed to establish security measures on your website, they automatically conclude that you are either completely negligent in securing your website or are extremely ignorant about information security challenges and threads. Such conclusions can be devastating for your organization’s image.
- Security audits and penetration testing: Unpatched systems are a prime target for hackers since they are susceptible to numerous vulnerabilities. Other known vulnerabilities are unused open ports on servers which allow attackers to connect to servers without authentication, allowing remote execution of malicious code when connected to an unsecured networks. Regular security audits are helpful in evaluating the security posture of an IT infrastructure (operating systems, service and application flaws, improper configurations, or risky end-user behaviour) and better protect the systems hosting the website
- Defend yourself against SQL injection attacks: SQL injection attacks involve the use of SQL statements inserted into data entry fields in order to affect the execution of predefined SQL statements. With the modified SQL statements, attackers have extracted sensitive information, obtained the authentication details of registered users on a website and corrupted databases making websites unusable. To defend against SQL injection, use parameterized statements that make sure that the inputs passed into SQL statements are treated in a safe manner. Escaping inputs from input fields which treats all inputs, especially special characters as part of the string, not the end of the string, also defends against SQL Injection
- Defend yourself against Cross-site Scripting (XSS) attacks: Cross site scripting is when an attacker tries to pass scripting code into a web form to attempt to run unauthorized code on the website. It tricks an application into sending malicious script through the browser, which believes the scropt is coming from the trusted website. Each time an end user accesses the affected page, their browser will download and run the malicious script as if it was part of the page. To defend against XSS, validate the input which ensures the application renders the correct data and prevents malicious data from doing harm to the site, database and users.
- Use defacement monitoring and detection tools: The effects of web attacks are leaving companies with a short time to react and perform damage control after an incident. Defacement monitoring and detection tools are one of the best solutions to monitor any defacement or unauthorized integrity change in the websites. These are some of the most used monitoring and detection tools: Banff Cyber’s WebOrion Defacement Monitor, Site24x7 and Nagios. Careful evaluation and configuration of the tools to detect both full and partial defacements involving HTML as well as linked images, scripts and stylesheets are important to ensure an effective tool is in place.
- Prepare to respond to defacement incidents: What do we do when our website is defaced? A good detection tool only tells you when your website is defaced but not the action that is to be taken. It is therefore important to put in place a set of incident response procedures, and ensure that you have the right personnel to respond to a web defacement. The technical response team will likely involve the security manager, web masters/web developers and the web server team. It may also be important to have corporate communications prepare a public message to preserve the web reputation of the company and also have a maintenance webpage to inform customers. Make an action plan for handling the restoration process that will shorten the time for recovery.
Here are general minimal tips and advice from CERT-GH as precaution steps:
- Do not click on any email attachment or links provided in emails, social media platforms or websites that you are not familiar with.
- Apply security updates and patches and stay up to date with the latest system versions.
- Report the incident to CERT-Gh on report@cybersecurity.gov.gh
- Share the advisory and precaution steps among users in your organization and communities for awareness purposes.
Best Advice:
Website defacement can result in damage to a site’s reputation, loss of valuable information and user privacy, loss of money and loss of time. It is therefore expedient to put mitigation and prevention techniques in place. To conclude, keep these tips:
- Keep software up to date
- Watch out for SQL injection
- Protect against XSS attacks
- Beware of error messages
- Validate on both the browser and the server side
- Check your passwords
- Avoid file uploads by users
- User HTTPS
- Get website security tools
How to Recognize and Avoid Phishing Scams
Scammers use email or text messages to trick you into giving them your personal information. They may try to steal your passwords, account numbers, or Social Security numbers. If they get that information, they could gain access to your email, bank, or other accounts. Scammers launch thousands of phishing attacks every day and they’re often successful. But there are several things you can do to protect yourself.
Scammers use familiar company names or pretend to be someone you know. They ask you to click on a link or give passwords or bank account numbers. If you click on the link, they can install programs that lock you out of your computer and can steal your personal information. They pressure you to act now – or something bad will happen.
Check it out.
Look up the website or phone number for the company or person who’s
contacting you. Call that company or person directly. Use a number you
know to be correct, not the number in the email or text. Tell them about
the message you got
Look for scam tip-offs.
- You don’t have an account with the company.
- The message is missing your name or uses bad grammar and spelling.
- The person asks for personal information, including passwords.
- But note: some phishing schemes are sophisticated and look very real, so check it out and protect yourself.
- Just place your cursor on the link you have been asked to click to verify the web address.
Keep your computer security up to date by installing an antivirus, update
it regularly and back up your data often.
Consider multi-factor authentication – a second step to verify who you
are, like a text with a code – for accounts that support it.
Change any compromised passwords right away and don’t use them for
any other accounts.
Advisory On RDP Brute Force Attacks
A way for employees to access corporate devices is by using Remote
Desktop
Protocol (RDP). Remote Desktop is a remote management tool which allows you to connect
to any
computer and take over the desktop. It’s like you are sitting and looking at your own
computer,
only remotely. It is highly used especially during this pandemic situation, for those
who have
moved to work from home. If poorly configured, it might be vulnerable to attacks.
- RDP devices are exposed to the internet
- RDP ports and services are being used as the initial attack vector in ransomware attacks
- Brute-force attacks have been increasing
- After successfully gaining credentials, attackers get full access to the corporate IT resources
- Leakage of sensitive information
- Spread of malware infection
- Use strong and complex passwords on RDP servers
- Use corporate VPN when connecting remote devices
- Use two-factor authentication where possible
- Disable RDP port (3389) when not in use
- Enable account lockout policies to block brute-force attacks after number of failed login attempts
- Enable account audit policies to see login errors
References
https://www.bleepingcomputer.com/news/security/rdp-brute-force-attacks-are-skyrocketing-due-to-remote-working/