A buffer overflow vulnerability has been discovered in Astrolog v7.70, a popular open-source astrology software. This vulnerability allows an attacker to execute arbitrary code or cause a Denial of Service (DoS) by supplying an overly long environment variable to the FileOpen function.
CVE ID: CVE-2025-29625
Vulnerability Type: Buffer Overflow
Impact: Remote Code Execution (RCE) & Denial of Service (DoS)
Attack Vector: Local (via environment variables)
Technical Details
The vulnerability exists in the following section of the FileOpen function, where the program reads environment variables and constructs file paths using sprintf without proper bounds checking:
Memory is an important part of a computer system that is used to store data. The process of memory management is critical because there is a limited amount of memory available to a computer system. One of the most important parts in the kernel of an operating system is the memory management part. In this section, the kernel has the task of making the memory available to the executive units (like processes or threads) by effectively communicating with the memory management unit in the processor, or in other words, allocating the memory to them.
Now, I guess we are ready to make our hands dirty by writing a simple fuzzer. I start with Generation Based Fuzzers. As we discussed in Part 1, generation-based fuzzers are a kind of fuzzers that generate input from scratch. As I mentioned befre, they can be divided into two categories: smart fuzzers and dumb fuzzers. Smart fuzzers recognize the input structure, but dumb fuzzers don’t.
Dumb Generation-Based Fuzzers
In this part, I use C++ language to create a simple dumb generation-based fuzzer but basically, the concepts are the same so you can choose your own programming language to continue the tutorial.
Before getting into fuzzer internals, it’s necessary to understand the minimum concept of vulnerabilities and anything related to them. In this part, the fundamental concept is explained. I hope it will be useful for you.
Understanding Vulnerability Analysis
Vulnerability analysis is the process of identifying, assessing, and prioritizing the security weaknesses in a system. Vulnerability analysis is important for maintaining the confidentiality, integrity, and availability of the data and services that the system provides. It is a critical component of any comprehensive security strategy, as it allows organizations to proactively address potential threats before they can be exploited by malicious actors.
I decided to study Fuzzers and in this way, I wanna teach what I learn through my research. Let’s get to it.
Software Security
Software security is a critical aspect of software development that focuses on safeguarding software applications from potential threats. This involves a set of practices that are integrated into the software development process to prevent unauthorized access, use, disclosure, disruption, modification, or destruction. Software security testing can be introduced at various organizations of: