A flaw was found in ImageMagick in coders/webp.c. An attacker who submits a crafted file that is processed by ImageMagick could trigger undefined behavior in the form of math division by zero. The highest threat from this vulnerability is to system availability. This vulnerability is classified as medium severity, with a CVSS score of 5.5, indicating that it poses a moderate risk to systems that utilize ImageMagick.
Organizations should prioritize patching immediately. The nature of this vulnerability, which involves a local attack vector and requires user interaction, means that it can be exploited under specific conditions. The lack of required privileges for exploitation adds to the risk, as it allows attackers to leverage this flaw without elevated access.
While there is currently no known public exploit for this vulnerability, the potential impact on system availability necessitates that organizations using ImageMagick remain vigilant and proactive in addressing this issue.
To further understand the implications of this vulnerability, organizations should consider their specific deployment environments and the likelihood of encountering maliciously crafted files. The urgency for remediation is underscored by the CVSS score, which indicates a medium-level risk.
Vulnerability Details
The vulnerability described in CVE-2021-20245 affects ImageMagick, specifically within the coders/webp.c file. The official description notes that an attacker can exploit this flaw by submitting a specially crafted file to ImageMagick, causing a division by zero error. The CVSS version 3.1 score of 5.5 indicates a medium severity level, with the availability impact rated as high. The vulnerability affects multiple versions of ImageMagick, Debian, Fedora, and Red Hat systems.
The relevant CWE classification for this vulnerability is CWE-369, which pertains to division by zero errors. The flaw's attack vector is local, and it requires low complexity to exploit due to the lack of authentication or elevated privileges, making it easier for attackers to leverage.
Technical Analysis
The root cause of this vulnerability lies in the handling of inputs by ImageMagick's webp.c coding module. When a crafted file is processed, the software fails to properly manage certain mathematical operations, leading to potential undefined behavior. This can result in a division by zero, causing the application to crash or behave unexpectedly.
The attack vector is local, which means the attacker must have some level of access to the machine where ImageMagick is installed. The attack complexity is low, as it does not require significant effort or specialized knowledge to exploit this vulnerability. User interaction is required, as the crafted file must be submitted for processing.
In terms of impact, the vulnerability affects availability significantly, potentially bringing down the application or service that relies on ImageMagick. However, there is no impact on confidentiality or integrity, as the vulnerability does not expose sensitive data or allow unauthorized modification.
Risk & Impact Analysis
Risk to organizations includes potential downtime or service disruption due to the undefined behavior caused by the flaw. The availability impact is categorized as high, which means that organizations relying on ImageMagick for processing images must consider the implications of this vulnerability seriously.
Given that this vulnerability requires user interaction, the likelihood of exploitation may be lower in some environments. However, organizations should not underestimate the risk, especially if they process files from untrusted sources. The presence of a medium CVSS score indicates that while the risk is moderate, it should not be ignored.
Organizations should assess the blast radius of this vulnerability, considering how widespread ImageMagick is in their environment. If ImageMagick is used extensively, the potential impact could affect multiple services and applications, increasing the urgency to address the issue.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The vulnerability affects multiple versions of ImageMagick, specifically versions prior to 6.9.11-62 and versions from 7.0.0 to 7.0.10-62. Additionally, it impacts several distributions including Debian (version 9.0), Fedora (version 33), and various Red Hat Enterprise Linux versions (6.0, 7.0, and 8.0).
Mitigation & Remediation
Organizations should prioritize patching immediately by upgrading to the latest version of ImageMagick, specifically to versions 6.9.11-62 or 7.0.10-62 and later. If immediate patching is not feasible, consider implementing workarounds such as restricting access to ImageMagick or disabling features that process potentially unsafe files.
Additionally, configuration hardening practices should be employed to limit the exposure of ImageMagick to untrusted inputs. Network controls can be established to monitor and filter the types of files submitted for processing, and organizations should enhance their monitoring to detect any abnormal behavior indicative of exploitation attempts.
Continuous security testing can also help validate the effectiveness of the applied remediation measures.
Detection Guidance
Organizations should monitor logs for indicators of exploitation attempts, such as unusual file processing requests or crashes related to ImageMagick. Behavioral anomalies in the system, particularly when processing files, should also be investigated. Network signatures that detect abnormal file submissions can provide an additional layer of defense against exploitation.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2021-20245 lies in the recurring vulnerabilities associated with file processing libraries like ImageMagick. As more organizations rely on image manipulation in applications, the potential for exploitation increases. Security teams should take this opportunity to review their image processing practices and implement robust security measures.
This vulnerability also highlights the importance of proactive security assessments, as even well-known libraries can harbor critical flaws. Lessons learned from this incident can inform future development and operational strategies, fostering a culture of security awareness.
For organizations looking to strengthen their defenses, consider exploring our application security assessment services to identify potential weaknesses in their systems.
Moreover, understanding the patterns of such vulnerabilities can guide teams in developing better security practices. Engaging in red teaming exercises can also provide invaluable insights into the effectiveness of existing security controls.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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