CVE-2017-7960 in libcroco
Summary
by MITRE
The cr_input_new_from_uri function in cr-input.c in libcroco 0.6.11 and 0.6.12 allows remote attackers to cause a denial of service (heap-based buffer over-read) via a crafted CSS file.
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Analysis
by VulDB Data Team • 12/01/2022
The vulnerability identified as CVE-2017-7960 resides within the libcroco library version 0.6.11 and 0.6.12, specifically within the cr_input_new_from_uri function located in the cr-input.c source file. This flaw represents a heap-based buffer over-read condition that can be exploited by remote attackers through the manipulation of crafted CSS files. The issue occurs when the library processes input from URI sources without adequate bounds checking, allowing maliciously constructed CSS content to trigger memory access violations. Such vulnerabilities fall under the category of memory safety issues and are classified as CWE-125 in the Common Weakness Enumeration catalog, which details out-of-bounds read conditions that can lead to system instability or information disclosure.
The technical exploitation of this vulnerability requires an attacker to craft a specially designed CSS file that, when processed by the vulnerable libcroco library, causes the cr_input_new_from_uri function to attempt reading beyond the allocated heap buffer boundaries. This over-read condition typically manifests as a segmentation fault or memory corruption that can result in application crashes, making the affected system unavailable to legitimate users. The vulnerability demonstrates characteristics consistent with the ATT&CK technique T1499.004, which involves network denial of service attacks targeting application availability through memory corruption vulnerabilities.
The operational impact of CVE-2017-7960 extends beyond simple service disruption, as it can affect any software application that relies on libcroco for CSS processing, including web browsers, content management systems, and document processing applications. When exploited, this vulnerability can lead to cascading failures in systems that depend on proper CSS parsing, potentially allowing attackers to consume system resources through repeated exploitation attempts or to cause more severe memory corruption that might be leveraged for additional attack vectors. The vulnerability affects the broader ecosystem of applications that utilize the libcroco library, making it a significant concern for software vendors and system administrators who must consider the potential for widespread impact across their infrastructure.
Mitigation strategies for CVE-2017-7960 primarily involve upgrading to a patched version of the libcroco library, specifically versions that address the heap-based buffer over-read condition in the cr_input_new_from_uri function. Organizations should also implement input validation measures that filter or sanitize CSS content before processing, particularly when dealing with untrusted inputs from external sources. Additionally, deploying intrusion detection systems that can identify patterns associated with malicious CSS file construction and implementing application-level sandboxing techniques can provide additional defense layers. The vulnerability underscores the importance of maintaining updated third-party libraries and following secure coding practices that include proper bounds checking and memory management to prevent similar issues from occurring in future software releases.