Vulnerability Scan Result
| Title: | Oliver Schöttner - Softwareentwickler |
| Description: | Oliver Schöttner - Softwareentwickler aus Ingolstadt |
| ip_address | 38.242.157.171 |
| country | DE  |
| network_name | Contabo GmbH |
| asn | AS51167 |
22/tcp | ssh | OpenSSH 9.6p1 Ubuntu 3ubuntu13.14 |
80/tcp | http | Golang net/http server - |
443/tcp | https | Golang net/http server - |
3306/tcp | mysql | - - |
8080/tcp | https | Golang net/http server - |
| Software / Version | Category |
|---|---|
| Nginx 1.29.1 | Web servers, Reverse proxies |
| Open Graph | Miscellaneous |
| HSTS | Security |
| YouTube | Video players |
Web Application Vulnerabilities
Evidence
| Software / Version | Category |
|---|---|
| Nginx 1.29.1 | Web servers, Reverse proxies |
| Open Graph | Miscellaneous |
| HSTS | Security |
| YouTube | Video players |
Vulnerability description
We noticed that server software and technology details are exposed, potentially aiding attackers in tailoring specific exploits against identified systems and versions.
Risk description
The risk is that an attacker could use this information to mount specific attacks against the identified software type and version.
Recommendation
We recommend you to eliminate the information which permits the identification of software platform, technology, server and operating system: HTTP server headers, HTML meta information, etc.
Evidence
| URL | Evidence |
|---|---|
| https://schoettner.dev/ | Response headers do not include the HTTP Strict-Transport-Security header |
Vulnerability description
We noticed that the target application lacks the HTTP Strict-Transport-Security header in its responses. This security header is crucial as it instructs browsers to only establish secure (HTTPS) connections with the web server and reject any HTTP connections.
Risk description
The risk is that lack of this header permits an attacker to force a victim user to initiate a clear-text HTTP connection to the server, thus opening the possibility to eavesdrop on the network traffic and extract sensitive information (e.g. session cookies).
Recommendation
The Strict-Transport-Security HTTP header should be sent with each HTTPS response. The syntax is as follows: `Strict-Transport-Security: max-age=<seconds>[; includeSubDomains]` The parameter `max-age` gives the time frame for requirement of HTTPS in seconds and should be chosen quite high, e.g. several months. A value below 7776000 is considered as too low by this scanner check. The flag `includeSubDomains` defines that the policy applies also for sub domains of the sender of the response.
Classification
| CWE | CWE-693 |
| OWASP Top 10 - 2017 | |
| OWASP Top 10 - 2021 |
Evidence
| URL | Evidence |
|---|---|
| https://schoettner.dev/ | Response does not include the HTTP Content-Security-Policy security header or meta tag |
Vulnerability description
We noticed that the target application lacks the Content-Security-Policy (CSP) header in its HTTP responses. The CSP header is a security measure that instructs web browsers to enforce specific security rules, effectively preventing the exploitation of Cross-Site Scripting (XSS) vulnerabilities.
Risk description
The risk is that if the target application is vulnerable to XSS, lack of this header makes it easily exploitable by attackers.
Recommendation
Configure the Content-Security-Header to be sent with each HTTP response in order to apply the specific policies needed by the application.
Classification
| CWE | CWE-693 |
| OWASP Top 10 - 2017 | |
| OWASP Top 10 - 2021 |
Evidence
| URL | Evidence |
|---|---|
| https://schoettner.dev/ | Response headers do not include the Referrer-Policy HTTP security header as well as the |
Vulnerability description
We noticed that the target application's server responses lack the Referrer-Policy HTTP header, which controls how much referrer information the browser will send with each request originated from the current web application.
Risk description
The risk is that if a user visits a web page (e.g. "http://example.com/pricing/") and clicks on a link from that page going to e.g. "https://www.google.com", the browser will send to Google the full originating URL in the `Referer` header, assuming the Referrer-Policy header is not set. The originating URL could be considered sensitive information and it could be used for user tracking.
Recommendation
The Referrer-Policy header should be configured on the server side to avoid user tracking and inadvertent information leakage. The value `no-referrer` of this header instructs the browser to omit the Referer header entirely.
Classification
| CWE | CWE-693 |
| OWASP Top 10 - 2017 | |
| OWASP Top 10 - 2021 |
Evidence
| URL | Evidence |
|---|---|
| https://schoettner.dev/ | Response headers do not include the X-Content-Type-Options HTTP security header |
Vulnerability description
We noticed that the target application's server responses lack the X-Content-Type-Options header. This header is particularly important for preventing Internet Explorer from reinterpreting the content of a web page (MIME-sniffing) and thus overriding the value of the Content-Type header.
Risk description
The risk is that lack of this header could make possible attacks such as Cross-Site Scripting or phishing in Internet Explorer browsers.
Recommendation
We recommend setting the X-Content-Type-Options header such as `X-Content-Type-Options: nosniff`.
Classification
| CWE | CWE-693 |
| OWASP Top 10 - 2017 | |
| OWASP Top 10 - 2021 |
Evidence
Vulnerability description
We found the robots.txt on the target server. This file instructs web crawlers what URLs and endpoints of the web application they can visit and crawl. Website administrators often misuse this file while attempting to hide some web pages from the users.
Risk description
There is no particular security risk in having a robots.txt file. However, it's important to note that adding endpoints in it should not be considered a security measure, as this file can be directly accessed and read by anyone.
Recommendation
We recommend you to manually review the entries from robots.txt and remove the ones which lead to sensitive locations in the website (ex. administration panels, configuration files, etc).
Evidence
| URL | Method | Parameters | Evidence |
|---|---|---|---|
| https://schoettner.dev/ | GET | Headers: User-Agent=Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.0.0 Safari/537.36 | Email Address: oliver@schoettner.org oliver@schoettner.dev |
Vulnerability description
We noticed that this web application exposes email addresses, which might be unintended. While not inherently a vulnerability, this information could be leveraged in social engineering or spam related activities.
Risk description
The risk is that exposed email addresses within the application could be accessed by unauthorized parties. This could lead to privacy violations, spam, phishing attacks, or other forms of misuse.
Recommendation
Compartmentalize the application to have 'safe' areas where trust boundaries can be unambiguously drawn. Do not allow email addresses to go outside of the trust boundary, and always be careful when interfacing with a compartment outside of the safe area.
Classification
| CWE | CWE-200 |
| OWASP Top 10 - 2017 | |
| OWASP Top 10 - 2021 |
Vulnerability description
We have noticed that the server is missing the security.txt file, which is considered a good practice for web security. It provides a standardized way for security researchers and the public to report security vulnerabilities or concerns by outlining the preferred method of contact and reporting procedures.
Risk description
There is no particular risk in not having a security.txt file for your server. However, this file is important because it offers a designated channel for reporting vulnerabilities and security issues.
Recommendation
We recommend you to implement the security.txt file according to the standard, in order to allow researchers or users report any security issues they find, improving the defensive mechanisms of your server.
Infrastructure Vulnerabilities
Evidence
We managed to detect a publicly accessible SSH service. Starting Nmap ( https://nmap.org ) at 2026-01-28 14:28 EET Nmap scan report for schoettner.dev (38.242.157.171) Host is up (0.014s latency). rDNS record for 38.242.157.171: vmd178949.contaboserver.net
PORT STATE SERVICE VERSION 22/tcp open ssh OpenSSH 9.6p1 Ubuntu 3ubuntu13.14 (Ubuntu Linux; protocol 2.0) | ssh-auth-methods: | Supported authentication methods: | publickey |_ password Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ . Nmap done: 1 IP address (1 host up) scanned in 0.76 seconds
Vulnerability description
We found that the SSH service with username/password authentication is publicly accessible. Network administrators often use remote administration protocols to control devices like switches, routers, and other essential systems. However, allowing these services to be accessible via the Internet can increase security risks, creating potential opportunities for attacks on the organization.
Risk description
Exposing this service online with username/password authentication can enable attackers to launch authentication attacks, like guessing login credentials, and potentially gaining unauthorized access. Vulnerabilities, such as unpatched software, protocol flaws, or backdoors could also be exploited. An example is the CVE-2024-3094 (XZ Utils Backdoor) vulnerability.
Recommendation
We recommend turning off SSH with username/password authentication access over the Internet and instead using a Virtual Private Network (VPN) that mandates two-factor authentication (2FA). If the SSH service is essential for business purposes, we recommend limiting access only from designated IP addresses using a firewall. Furthermore, it is advisable to utilize SSH Public Key Authentication since it employs a key pair to verify the identity of a user or process.
Evidence
We checked 2056 selectors but found no DKIM records.
Vulnerability description
We found that no DKIM record was configured. When a DKIM (DomainKeys Identified Mail) record is not present for a domain, it means that outgoing emails from that domain are not cryptographically signed. DKIM is a critical component of email authentication, allowing recipients to verify that an email was genuinely sent from an authorized server and that the message has not been altered in transit. The absence of a DKIM record leaves the domain vulnerable to email spoofing and phishing attacks, as attackers can send fraudulent emails that appear to originate from the domain without any cryptographic verification.
Risk description
Without a DKIM record, recipients have no way of verifying the integrity or authenticity of emails sent from the domain. This increases the likelihood of phishing and spoofing attacks, where malicious actors impersonate the domain to send fraudulent emails. This can lead to significant security incidents, such as credential theft, financial fraud, or the distribution of malware. Additionally, many email providers use DKIM as part of their spam and reputation filters, meaning that emails from a domain without DKIM may be flagged as spam or rejected, impacting the deliverability and reputation of legitimate emails.
Recommendation
We recommend implementing DKIM for your domain to enhance email security and protect your brand from email-based attacks. Generate a DKIM key pair (public and private keys), publish the public key in the DNS under the appropriate selector, and configure your email servers to sign outgoing messages using the private key. Ensure that the DKIM key length is at least 1024 bits to prevent cryptographic attacks. Regularly monitor DKIM signatures to ensure the system is functioning correctly and update keys periodically to maintain security.
Evidence
We found insecure DNS cookie usage on the following nameservers: ns.udag.net, ns.udag.org, ns.udag.de
Vulnerability description
We found that the server does not implement DNS Cookies or uses them insecurely. DNS Cookies help prevent DNS-based attacks, such as spoofing and amplification attacks.
Risk description
The risk exists because without DNS Cookies, the server is vulnerable to DNS spoofing and amplification attacks. Attackers can manipulate responses or use the server in distributed denial-of-service (DDoS) attacks, compromising network availability and security.
Recommendation
We recommend enabling DNS Cookies to prevent spoofed DNS responses. Ensure proper cookie validation is implemented to mitigate DNS amplification attacks. Regularly update DNS servers to support the latest DNS security features.
Evidence
| Domain Queried | DNS Record Type | Description | Value |
|---|---|---|---|
| schoettner.dev | TXT | Text record | "apple-domain=YZ6tBh8oVoVa06pb" |
Vulnerability description
We found that the target server has no DMARC policy configured. A missing DMARC (Domain-based Message Authentication, Reporting, and Conformance) policy means that the domain is not enforcing any DMARC policies to protect against email spoofing and phishing attacks. Without DMARC, even if SPF (Sender Policy Framework) or DKIM (DomainKeys Identified Mail) are configured, there is no mechanism to tell receiving email servers how to handle messages that fail authentication. This leaves the domain vulnerable to abuse, such as email spoofing and impersonation.
Risk description
Without a DMARC policy, your domain is highly vulnerable to email spoofing, allowing attackers to impersonate your brand and send fraudulent emails that appear legitimate. This can lead to phishing attacks targeting your customers, employees, or partners, potentially resulting in stolen credentials, financial loss, or unauthorized access to sensitive systems. Additionally, repeated spoofing attempts can severely damage your brand's reputation, as recipients may lose trust in communications from your domain, associating your brand with malicious activity. The absence of DMARC also prevents you from monitoring and mitigating email-based attacks, leaving your domain exposed to ongoing abuse.
Recommendation
We recommend implementing a DMARC policy for your domain. Start by configuring a DMARC record with a policy of p=none, which will allow you to monitor email flows without impacting legitimate emails. This initial setup helps identify how emails from your domain are being processed by recipient servers. Once you’ve verified that legitimate emails are passing SPF and DKIM checks, you can gradually enforce stricter policies like p=quarantine or p=reject to protect against spoofing and phishing attacks. Additionally, include rua and ruf email addresses in the DMARC record to receive aggregate and forensic reports. These reports will provide valuable insights into authentication failures and help you detect any spoofing attempts.
Evidence
| Domain Queried | DNS Record Type | Description | Value |
|---|---|---|---|
| schoettner.dev | SPF | Sender Policy Framework | "v=spf1 redirect=icloud.com" |
Evidence
| Operating System | Accuracy |
|---|---|
| Linux 5.0 - 5.4 | 98% |
Vulnerability description
OS Detection
Evidence
| Domain Queried | DNS Record Type | Description | Value |
|---|---|---|---|
| schoettner.dev | A | IPv4 address | 38.242.157.171 |
| schoettner.dev | NS | Name server | ns.udag.net |
| schoettner.dev | NS | Name server | ns.udag.org |
| schoettner.dev | NS | Name server | ns.udag.de |
| schoettner.dev | MX | Mail server | 10 mx01.mail.icloud.com |
| schoettner.dev | MX | Mail server | 10 mx02.mail.icloud.com |
| schoettner.dev | SOA | Start of Authority | ns.udag.de. hostmaster.united-domains.de. 2024100708 10800 3600 604800 3600 |
| schoettner.dev | TXT | Text record | "apple-domain=YZ6tBh8oVoVa06pb" |
| schoettner.dev | SPF | Sender Policy Framework | "v=spf1 redirect=icloud.com" |
Risk description
An initial step for an attacker aiming to learn about an organization involves conducting searches on its domain names to uncover DNS records associated with the organization. This strategy aims to amass comprehensive insights into the target domain, enabling the attacker to outline the organization's external digital landscape. This gathered intelligence may subsequently serve as a foundation for launching attacks, including those based on social engineering techniques. DNS records pointing to services or servers that are no longer in use can provide an attacker with an easy entry point into the network.
Recommendation
We recommend reviewing all DNS records associated with the domain and identifying and removing unused or obsolete records.
Evidence
| Software / Version | Category |
|---|---|
| YouTube | Video players |
| Nginx 1.29.1 | Web servers, Reverse proxies |
| HSTS | Security |
Vulnerability description
We noticed that server software and technology details are exposed, potentially aiding attackers in tailoring specific exploits against identified systems and versions.
Risk description
The risk is that an attacker could use this information to mount specific attacks against the identified software type and version.
Recommendation
We recommend you to eliminate the information which permits the identification of software platform, technology, server and operating system: HTTP server headers, HTML meta information, etc.