Tag: PentestChronicles

Articles tagged with PentestChronicles

← Back to all tags

PentestChronicles Articles

Illustration of Let the framework guard your JWT internals - but who is guarding the framework?

Let the framework guard your JWT internals - but who is guarding the framework?

Marek Kaliszczyk

26 September, 2025

During a recent security assessment, we found a critical authentication bypass, which at the first glance looked like a classic Json Web Token (JWT) issue - no cryptographic signature verification and possibility to forge valid tokens as a result. A blackbox assessment would probably have called it a day and reported the issue as a lack of cryptographic signature verification, which would be a legitimate issue. However, since the assessment consisted of whitebox code review, it was possible to dive deeper into the application's logic.

Illustration of Accessing Internal Network by WiFi Hacking - 2024 Pentest Case

Accessing Internal Network by WiFi Hacking - 2024 Pentest Case

Aleksander Wojdyła

25 October, 2024

During the last penetration test, I performed an Evil Twin attack, which involves setting up a fake access point with the same name as the legitimate one. Due to improper configuration of endpoint devices (e.g., computers, phones, tablets), users could accept an incorrect (fake, generated by the auditor) certificate identifying the network. This led to a successful capture of the authentication segment of the communication. Subsequently, the auditor subjected the captured data to brute-force attacks, resulting in the retrieval of credentials.

Illustration of From SOQL Query to Data Breach - Lessons from a Real-World Pentest

From SOQL Query to Data Breach - Lessons from a Real-World Pentest

18 October, 2024

During one of security audits of a web application, I uncovered an interesting vulnerability: the exposure of an endpoint that allows users to perform arbitrary Salesforce Object Query Language (SOQL) queries. Such functionality, when available to unauthorized users or misconfigured, poses significant security risk, especially if Row-Level Security (RLS) permissions are not properly set. In this article I will analyze technical aspects of this vulnerability, the potential risks, and steps to mitigate such issues.

Illustration of Bypassing Host Validation: Real Pentest Case of Sensitive Data Exposure

Bypassing Host Validation: Real Pentest Case of Sensitive Data Exposure

MATEUSZ Kowalczyk

11 October, 2024

During one of penetration tests, I discovered a vulnerability that allowed us to bypass a host whitelist, leading to the exposure of sensitive data. This behavior could let attackers to exfiltrate sensitive information, such as password reset tokens, to external hosts they control. The severity of this vulnerability is significant, as it opens up further attack vectors that could potentially compromise the application and its users.

Illustration of Hacking IBM AS/400 in 2024: QShell and Remote Code Execution

Hacking IBM AS/400 in 2024: QShell and Remote Code Execution

MATEUSZ Kowalczyk

04 October, 2024

A few months ago, one of our clients commissioned us to audit a customer service application that continued to use the IBM AS400 environment. These days, an emulator is needed to connect to this application. An AS/400 emulator is software designed to emulate the functionality of an AS/400 system on a different platform, such as a modern desktop or server computer. These emulators enable users to access and interact with AS/400 applications and resources without the need for physical AS/400 hardware.

Illustration of Heartbleed Vulnerability in 2024: A Fresh Case from Our Pentest

Heartbleed Vulnerability in 2024: A Fresh Case from Our Pentest

Paweł Różański

20 September, 2024

During a recent security audit, vulnerability known as The Heartbleed Bug was discovered on two publicly accessible servers. What is interesting it is a fact that this vulnerability was discovered 10 years ago! It allows an attacker to access data directly from the memory of vulnerable systems. In fact, it enables the extraction of sensitive information, including credentials, without any pre-existing access or authentication requirements.

Illustration of Denial of Service Due to Improper Handling of Decimal Values

Denial of Service Due to Improper Handling of Decimal Values

13 September, 2024

During one of my recent pentests, I found an interesting Denial of Service (DoS) vulnerability that allows an attacker to cause the server to become unavailable. The severity of this vulnerability has been classified as HIGH because it can be exploited with a single HTTP request.

Illustration of From low-privileged user to Remote Code Execution: step-by-step pentest journey

From low-privileged user to Remote Code Execution: step-by-step pentest journey

In the world of web application security, some vulnerabilities are naturally less impactful than others. We often hear about direct, short, and simple attacks that can compromise an entire server or application. Sometimes, however, it is chaining multiple, less dangerous vulnerabilities that leads to serious consequences. Here we will go through a case from one of the pentests from a couple of weeks ago, where having a low-privileged user account allowed us first to read the application source code, then to escalate to admin, and finally to obtain remote code execution.

Illustration of Few steps on how to take over a whole application

Few steps on how to take over a whole application

In a recent penetration test, I found a vulnerability in the password reset tokens within a system's audit trail functionality. This flaw can lead to arbitrary account takeover, allowing attackers to hijack user accounts, including those with high-level privileges.

Illustration of How a simple vulnerability allowed proxying TCP traffic - real pentest case

How a simple vulnerability allowed proxying TCP traffic - real pentest case

During a penetration test for our client, it was discovered that the turn.example.com server, which is part of the tested application infrastructure, is vulnerable. This flaw allows for proxying TCP traffic through the server, enabling attacks on any host on the internet. Additionally, attackers could gain access to internal systems and their configurations, potentially compromising the entire infrastructure.

Illustration of Exploiting PDF generation vulnerability: a case study from real pentest

Exploiting PDF generation vulnerability: a case study from real pentest

In a recent penetration test conducted by [Your Security Company], we identified a critical vulnerability within a web application that allowed unauthorized access to sensitive resources. This flaw permits an attacker to access both local server files and data on other servers within the same network. The vulnerability stems from improper handling of user-input data, presenting a severe security risk.

Illustration of Password reset flaw: when anyone can reset your password

Password reset flaw: when anyone can reset your password

During rigorous testing, security researchers uncovered a significant weakness in the password reset mechanisms used by numerous online platforms. By exploiting the seemingly harmless phone number field, an attacker can compromise a victim's account. The vulnerability lies in the mishandling of a four-digit code, which, instead of being sent solely to the owner's phone, is also included in the server's response. This oversight turns a seemingly harmless feature into a gateway for hackers to infiltrate users' digital lives.

Illustration of Why you shouldn't (again) roll your own cryptography - real-life case in 2024.

Why you shouldn't (again) roll your own cryptography - real-life case in 2024.

Mateusz Lewczak

In the last part of our series "Why You Shouldn't Roll Your Own Cryptography," I talked about a custom hashing algorithm using Triple-DES. Today, I'll present another case from a desktop application that used a completely custom "hashing" algorithm. It's important to note that the application was written in a native language, so some reverse engineering will be involved.

Illustration of Exploring DaaS Security - part 2: Other available applications on the machine (3rd party)

Exploring DaaS Security - part 2: Other available applications on the machine (3rd party)

Mateusz Lewczak

When dealing with applications used by regular company employees, often involved in paperwork, it's likely that cloud environments will also include office applications, image viewers, and possibly File Explorer. While these are not hacking tools, they can still be utilized in ways that facilitate access to the system's shell.

Illustration of Exploring DaaS Security: A Comprehensive Guide Based on Vulnerabilities Uncovered in Real Pentests - part 1

Exploring DaaS Security: A Comprehensive Guide Based on Vulnerabilities Uncovered in Real Pentests - part 1

Mateusz Lewczak

We're experiencing a real renaissance among desktop applications, thanks to cloud services that have added Desktop As A Service to their offerings. This service allows us to stream the image of a native application running on a cloud machine directly to our browser. We interact with it as we would with a normal application, except that, by design, we have limited access to the system. And that's our main goal as pentesters - to escape from the Matrix (application) into the system shell! In a conventional test of a desktop application, the focus is primarily on the application itself and its associated files. However, for applications running under DaaS, the audit extends to the entire runtime environment.

Illustration of Crashing servers with digits: floating-point numbers DoS vulnerabilities

Crashing servers with digits: floating-point numbers DoS vulnerabilities

A Denial-of-Service (DoS) attack is a malicious attempt to disrupt the normal functioning of a system or network, in this case – a web application. One sophisticated form of such an attack exploits vulnerabilities in the processing of floating-point numbers. In our scenario, attackers manipulate the system's handling of floating-point arithmetic, leading to inaccurate calculations and potential system failures. This method challenges the reliability of numerical computations and poses a serious threat to the stability and availability of targeted systems.

Illustration of Insider threat - The average insider threat attack scenario. How attackers can take over an entire domain in a few steps. Part 2.

Insider threat - The average insider threat attack scenario. How attackers can take over an entire domain in a few steps. Part 2.

DOMINIK ANTOŃCZAK

23 February, 2024

Have you ever wondered how little it takes to take over an Active Directory domain? Have you considered using some exploit? Nah, using exploits is not a fancy way and can be easily detected, and if anything, that option remains as a last resort. As savvy "hackers", we possess the right knowledge to navigate the network smoothly without making noise. Sometimes it takes a few steps, and just as Neil Armstrong said, it's one small step for man…, but for us hackers, taking over one system is a small step towards taking over the entire network. In this scenario, I'll demonstrate how the ability to analyze acquired information, coupled with a few sublime actions, was sufficient to take over the entire domain of a company consisting of 500-1000 users.

Illustration of Server shutdown via GraphQL during real-life pentest

Server shutdown via GraphQL during real-life pentest

KAMIL JAROSIŃSKI

19 February, 2024

GraphQL is a query language and environment created by Facebook in 2012 and released publicly in 2015. However, it has only gained significant popularity among developers and organizations in the last few years. Why is it so popular? GraphQL serves as an alternative to traditional API protocols, like REST, offering a more flexible and efficient way for client-server communication. The emergence of new technology opens up new perspectives and solves some problems, but unfortunately, it also introduces threats. This is the case with GraphQL. If used without proper knowledge, it could potentially allow for a DoS (Denial of Service) attack.

Illustration of Insider threat - why security measures don't matter. Part 1

Insider threat - why security measures don't matter. Part 1

Dominik Antończak

09 February, 2024

A sneaky security threat that combines Blind XSS with data exfiltration techniques poses a significant risk, allowing adversaries to insert persistent HTML/JavaScript code that executes within the domain context of an application. This vulnerability can be exploited to steal any data from the application or perform actions on behalf of another user.

Illustration of New Year, Fresh Vulnerabilities: Unmasking Hidden Threats in Web Applications

New Year, Fresh Vulnerabilities: Unmasking Hidden Threats in Web Applications

05 January, 2024

Security flaws, sometimes overlooked as minor ones, can escalate into significant risks for entire applications. Our recent penetration test identified a critical vulnerability enabling potential account takeover at the administrative level. This write-up highlights the essential need for comprehensive security measures throughout the application development process.

Illustration of The risks of over-logging: a case study on application takeover

The risks of over-logging: a case study on application takeover

15 November, 2023

Logs are often seen as a wall of text, filled with information that seems unimportant until a significant problem arises. Yet, have you ever thought about the security risks hidden within those walls of text, particularly when they include sensitive details like usernames and passwords? It's a common belief that only trustworthy individuals, such as administrators, access these logs, but not considering the potential security implications can be a dangerous oversight.

Illustration of Unveiling hidden data: a log file's security breach

Unveiling hidden data: a log file's security breach

10 November, 2023

Unveiling hidden data during 2023 pentest: how a misplaced log file can compromise 2FA security. Conducting penetration tests requires the use of existing solutions that significantly facilitate the work. For web applications, it is valuable to recognize the structure of directories or find files of interest. For this purpose, we can use applications such as: ffuf, dirbuster, gobuster. During the discussed test, I used the ffuf tool with a basic dictionary available publicly: https://github.com/danielmiessler/SecLists/blob/master/Discovery/Web-Content/common.txt

Illustration of Demystifying Prototype Pollution and its link to DOM XSS

Demystifying Prototype Pollution and its link to DOM XSS

Kalina Zielonka

03 October, 2023

JavaScript, the backbone of many web applications today, brings with it flexibility and potential. At the core of its architecture, every element we interact with is essentially an object, each with its own unique properties and methods. The Role of Prototypes in JavaScript Prototypes allow JS to share attributes or properties between different objects. Every object in JS has a prototype object associated with it, which gives that object its own properties. In other words, an object in JS inherits all the properties of its prototype.

Illustration of The Silent Threat of ReDoS: 2023 Real-Life Pentest Case

The Silent Threat of ReDoS: 2023 Real-Life Pentest Case

MATEUSZ LEWCZAK

26 September, 2023

Regular Expression Denial of Service (ReDoS) is a type of vulnerability that arises when an attacker submits a specially crafted input to an application that utilizes regular expressions to validate or process user input. The attacker's input aims to activate a slow or inefficient regex pattern, leading the application to consume excessive resources, such as CPU time or memory.

A professional cybersecurity consultant ready to assist with your inquiry.

Any questions?

Happy to get a call or email
and help!