Description Preview
A vulnerability has been identified in EmbedThis Appweb Community Edition 8.2.1, specifically in the src/http/httpLib.c file. The issue involves a null pointer dereference in the parseUri function when handling the stream parameter. This vulnerability allows attackers to cause a denial of service condition by sending specially crafted requests that trigger the null pointer dereference.
Overview
CVE-2021-33254 is a null pointer dereference vulnerability (CWE-476) affecting EmbedThis Appweb Community Edition 8.2.1. Appweb is a compact, high-performance web server designed for embedded systems and applications. The vulnerability exists in the parseUri function within the src/http/httpLib.c file, where improper validation of the stream parameter can lead to a null pointer dereference. When exploited, this vulnerability can cause the web server to crash, resulting in a denial of service condition that impacts the availability of the web server and any applications relying on it.
Remediation
To mitigate this vulnerability, system administrators and developers should:
- Update to the latest version of EmbedThis Appweb that contains the patch for this vulnerability.
- If immediate updating is not possible, implement network-level controls to restrict access to the Appweb server from untrusted networks.
- Monitor system logs for potential exploitation attempts.
- Consider implementing a web application firewall (WAF) to filter malicious requests.
- Apply the patch provided in the advisory if you need to continue using version 8.2.1.
References
- Detailed analysis and exploit information: https://awxylitol.github.io/2021/05/09/embedthis-appweb-npd-bug.html
- CWE-476: Null Pointer Dereference - https://cwe.mitre.org/data/definitions/476.html
- EmbedThis Appweb documentation - https://www.embedthis.com/appweb/
Industry ExposureMost to leastThis section illustrates the prevalence of a specific Common Vulnerabilities and Exposures (CVE) across various industries based on customer reports. The ranking displays industries from the most to least affected by this particular vulnerability, offering valuable insight into where this CVE has been most frequently observed. This information can help organizations within these sectors prioritize their security efforts, understand their relative risk exposure compared to their peers, and focus remediation strategies where they are most needed. By understanding the industry-specific impact, organizations can make more informed decisions regarding patching, resource allocation, and overall risk management related to this CVE.
This section illustrates the prevalence of a specific Common Vulnerabilities and Exposures (CVE) across various industries based on customer reports. The ranking displays industries from the most to least affected by this particular vulnerability, offering valuable insight into where this CVE has been most frequently observed. This information can help organizations within these sectors prioritize their security efforts, understand their relative risk exposure compared to their peers, and focus remediation strategies where they are most needed. By understanding the industry-specific impact, organizations can make more informed decisions regarding patching, resource allocation, and overall risk management related to this CVE.
- Accommodation & Food ServicesAccommodation & Food Services
- Administrative, Support, Waste Management & Remediation ServicesAdministrative, Support, Waste Management & Remediation Services
- Agriculture, Forestry Fishing & HuntingAgriculture, Forestry Fishing & Hunting
- Arts, Entertainment & RecreationArts, Entertainment & Recreation
- ConstructionConstruction
- Educational ServicesEducational Services
- Finance and InsuranceFinance and Insurance
- Health Care & Social AssistanceHealth Care & Social Assistance
- InformationInformation
- Management of Companies & EnterprisesManagement of Companies & Enterprises
- ManufacturingManufacturing
- MiningMining
- Other Services (except Public Administration)Other Services (except Public Administration)
- Professional, Scientific, & Technical ServicesProfessional, Scientific, & Technical Services
- Public AdministrationPublic Administration
- Real Estate Rental & LeasingReal Estate Rental & Leasing
- Retail TradeRetail Trade
- Transportation & WarehousingTransportation & Warehousing
- UtilitiesUtilities
- Wholesale TradeWholesale Trade
