CVE-2021-1577 in Application Policy Infrastructure Controller
Summary
by MITRE • 08/26/2021
A vulnerability in an API endpoint of Cisco Application Policy Infrastructure Controller (APIC) and Cisco Cloud Application Policy Infrastructure Controller (Cloud APIC) could allow an unauthenticated, remote attacker to read or write arbitrary files on an affected system. This vulnerability is due to improper access control. An attacker could exploit this vulnerability by using a specific API endpoint to upload a file to an affected device. A successful exploit could allow the attacker to read or write arbitrary files on an affected device.
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Analysis
by VulDB Data Team • 08/29/2021
The vulnerability identified as CVE-2021-1577 represents a critical access control flaw within Cisco's Application Policy Infrastructure Controller and Cloud Application Policy Infrastructure Controller platforms. These systems serve as central management points for Cisco's application policy infrastructure, handling critical network policy enforcement and configuration management functions. The vulnerability exists in an API endpoint that fails to properly validate access permissions, creating a pathway for unauthorized remote exploitation without requiring authentication credentials. This weakness directly impacts the fundamental security model of the platform, as it allows attackers to bypass normal authentication mechanisms and gain direct file system access to affected devices.
The technical implementation of this vulnerability stems from inadequate input validation and access control mechanisms within the API endpoint. Attackers can exploit this flaw by crafting specific API requests that leverage the vulnerable endpoint to upload files to the target system. Once successful, the attacker gains the ability to perform arbitrary read and write operations on the affected device's file system, potentially allowing for complete system compromise. The vulnerability's exploitation does not require any privileged credentials or complex attack vectors, making it particularly dangerous as it can be executed remotely by any attacker with network access to the target system. This flaw aligns with CWE-284, which specifically addresses improper access control vulnerabilities where systems fail to properly enforce access restrictions.
The operational impact of CVE-2021-1577 extends far beyond simple data theft, as it provides attackers with complete control over affected systems. Successful exploitation could enable attackers to install malicious software, modify critical system files, access sensitive network configurations, or even establish persistent backdoors within the network infrastructure. Given that APIC and Cloud APIC systems manage application policy enforcement across enterprise networks, compromise of these devices could result in widespread network disruption, unauthorized access to protected resources, and potential data breaches. The vulnerability affects organizations that rely on Cisco's application policy infrastructure for network security enforcement, potentially exposing their entire network to unauthorized control.
Organizations should implement immediate mitigations including network segmentation to limit access to APIC and Cloud APIC systems, deployment of firewall rules to restrict API endpoint access, and application of Cisco's official security patches. The ATT&CK framework categorizes this vulnerability under T1059 for command and scripting interpreter and T1078 for valid accounts, as attackers may leverage the compromised system to execute commands and maintain persistence. Additional protective measures include monitoring API endpoint access logs for suspicious activity, implementing network intrusion detection systems, and conducting regular vulnerability assessments. Organizations should also consider disabling unnecessary API endpoints and implementing multi-factor authentication for privileged access to reduce the attack surface and limit potential exploitation opportunities.