CVE-2025-0633 - A Sneak Peek into Heap-based Buffer Overflow in iniparser_dumpsection_ini() and How to Exploit it

Buffer overflow errors take place when we assign an amount of data that exceeds the capacity of the destination buffer. CVE-2025-0633 exposes a major heap-based buffer overflow vulnerability in iniparser_dumpsection_ini() function. It's essential to explore and understand the ins and outs of this vulnerability, how it could be exploited, and the potential impact of a successful exploit. In this blog post, we will take you through a detailed analysis of this vulnerability, look at some code snippets and provide the necessary information to understand and mitigate this risk.

CVE-2025-0633: Heap-based Buffer Overflow - An Overview

The developers of the iniparser library identified a crucial vulnerability within the iniparser_dumpsection_ini() function in the iniparser library. This type of vulnerability allows an attacker to read out of bound memory potentially resulting in memory corruption, data leaks, and crashes.

Technical Details

In order to understand how this vulnerability works, let's start by looking at the original source code of iniparser_dumpsection_ini() in iniparser.c:

    void iniparser_dumpsection_ini(dictionary * d, char * s, FILE * f)
    {
        int     i;
        char    keym[ASCIILINESZ+1];
        char    valm[ASCIILINESZ+1];
        char    tmp[ASCIILINESZ+1];
        int     j;

        if (!f) f = stdout;
        if (!d) return;
        if (!s) return;

        strncpy(tmp, s, ASCIILINESZ);
        tmp[strlen(tmp)+1] = '\';

        fprintf(f, "\n[%s]\n", s);
        strncpy(tmp, s, ASCIILINESZ);
        strncat(tmp, ":", 1);

        // Vulnerable block of code
        i = strlen(tmp);
        for (j = ; j < d->size; j++) {
            if (!strncmp(tmp, d->key[j], i)) {
                sprintf(keym, "%s", d->key[j]+i);
                iniparser_getstr_internal(d, d->key[j], valm);
                fprintf(f, "%-30s = %-30s\n", keym, valm);
            }
        }
    }

The vulnerability takes place within the vulnerable block of code highlighted above, where a missing bounds check on the lengths of the input section name (s) and the dictionary keys (d->key[j]) could lead to a heap-based buffer overflow in the variable 'keym' and 'valm'. By manipulating this overflow, an attacker can potentially read out of bounds memory content.

Exploiting the Vulnerability

It is important to understand the potential consequences of a successful exploit when mitigating such vulnerabilities. Although the vulnerability might seem small and harmless, the exploitation could have severe impacts. The readout of out-of-bounds memory content may leak sensitive data that can then be abused in various ways. This may result in memory corruption and application crashes leading to denial-of-service (DoS) attacks.

For more details, kindly refer to the original references and resources

1. iniparser GitHub Repository
2. Heap-based overflow vulnerability report for iniparser_dumpsection_ini()

Mitigating the Risk

As a developer of a project relying on iniparser, it's essential to keep an eye out for any security updates for the iniparser library. The security patch can be found within this PR.

Conclusion

To sum up, CVE-2025-0633 highlights a significant heap-based buffer overflow vulnerability present in the iniparser_dumpsection_ini() function. By understanding the vulnerability and its consequences, we can employ proper mitigation tactics to secure our applications. Remembering to keep libraries up-to-date, being vigilant, and considering alternative options for configuration management can go a long way in maintaining a secure application environment.

Timeline

Published on: 02/19/2025 07:15:33 UTC