CVE-2023-25088 in UR32L
Summary
by MITRE • 07/06/2023
Multiple buffer overflow vulnerabilities exist in the vtysh_ubus binary of Milesight UR32L v32.3.0.5 due to the use of an unsafe sprintf pattern. A specially crafted HTTP request can lead to arbitrary code execution. An attacker with high privileges can send HTTP requests to trigger these vulnerabilities.This buffer overflow occurs in the firewall_handler_set function with the index and description variables.
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Analysis
by VulDB Data Team • 11/06/2025
The CVE-2023-25088 vulnerability represents a critical buffer overflow flaw in the vtysh_ubus binary component of Milesight UR32L network security appliances running firmware version 32.3.0.5. This vulnerability stems from improper input validation and unsafe string handling practices within the firewall_handler_set function, which processes network firewall configuration parameters. The flaw manifests when the system processes HTTP requests containing specially crafted index and description variables, creating conditions where attacker-controlled data can overwrite adjacent memory regions beyond the intended buffer boundaries. The vulnerability is particularly concerning as it exists within a privileged binary that handles critical network security functions, making it a prime target for exploitation by adversaries seeking to compromise network infrastructure.
The technical implementation of this vulnerability follows a classic buffer overflow pattern where the unsafe sprintf function is employed without proper bounds checking or input length validation. When the firewall_handler_set function processes HTTP requests, it accepts user-supplied index and description parameters that are directly fed into the sprintf formatting operation without adequate size constraints. This creates a condition where maliciously crafted input can exceed the allocated buffer space, leading to memory corruption that can be exploited to overwrite return addresses, function pointers, or other critical program state information. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, which represents one of the most common and dangerous types of buffer overflow vulnerabilities in network security appliances.
The operational impact of this vulnerability extends beyond simple memory corruption, as it enables arbitrary code execution within the context of the vtysh_ubus binary process. An attacker with high privileges can leverage this vulnerability to execute malicious code on the affected device, potentially gaining complete control over the network security appliance. This compromise could result in unauthorized network access, data exfiltration, or the ability to manipulate firewall rules to allow malicious traffic while blocking legitimate communications. The vulnerability's exploitation requires an attacker to already possess high-privilege credentials, but this access level is often sufficient to establish persistent access to network infrastructure. The attack surface is particularly significant given that the affected device serves as a core network security component, potentially providing attackers with a foothold for broader network infiltration.
Mitigation strategies for CVE-2023-25088 should prioritize immediate firmware updates from Milesight to address the underlying buffer overflow vulnerability. Organizations should also implement network segmentation and access controls to limit the potential impact of exploitation, ensuring that only authorized personnel can access the device's administrative interfaces. Additional protective measures include monitoring for suspicious HTTP requests and implementing intrusion detection systems that can identify patterns consistent with buffer overflow exploitation attempts. Security teams should also conduct thorough vulnerability assessments of similar network security appliances within their environment, as the unsafe sprintf pattern may be present in other components. The vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1566 for phishing, as attackers may leverage this vulnerability to establish persistent access through compromised administrative credentials. Organizations should also consider implementing runtime protections such as stack canaries or address space layout randomization to make exploitation more difficult even if the underlying vulnerability cannot be immediately patched.