CVE-2017-15070 in Puma
Summary
by MITRE
The Intel Puma 5, 6, and 7 chips, as used on various Linksys devices, allow remote attackers to cause a denial of service (performance degradation) by sending a moderate volume of small packets to many TCP or UDP ports. NOTE: Intel has advised that they are only a hardware manufacturer in this instance; they do NOT own the mitigation distribution channel for these chips. Any details about mitigations would need to come from Linksys.
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Analysis
by VulDB Data Team • 11/22/2019
The vulnerability identified as CVE-2017-15070 represents a significant denial of service weakness affecting Intel Puma 5, 6, and 7 chips integrated into various Linksys networking devices. This flaw operates at the hardware level within the chip architecture, specifically targeting the network processing capabilities of these devices. The vulnerability manifests when remote attackers exploit the chip's handling of network traffic through a technique known as port exhaustion or resource exhaustion. The attack vector involves sending a moderate volume of small packets to numerous TCP or UDP ports simultaneously, which causes the affected devices to experience severe performance degradation or complete service disruption. This type of attack falls under the category of resource exhaustion attacks as defined by the Common Weakness Enumeration framework under CWE-400, where insufficient resource management leads to system instability and denial of service conditions.
The technical implementation of this vulnerability stems from how the Puma chip family processes incoming network packets and manages port states within its network stack. When multiple small packets are directed toward various ports on the device, the chip's processing capabilities become overwhelmed, leading to a cascading effect that degrades overall network performance. The attack requires relatively modest packet volumes compared to other denial of service methods, making it particularly dangerous as it can be executed with minimal resources and network bandwidth. This characteristic aligns with the ATT&CK framework's T1498 technique for Network Denial of Service, where adversaries leverage system weaknesses to disrupt network services. The hardware-based nature of this vulnerability means that traditional software-based mitigations are insufficient, as the root cause exists within the chip's firmware and hardware processing logic rather than the operating system or application layers.
The operational impact of CVE-2017-15070 extends beyond simple network disruption to potentially affect business continuity and network availability for organizations relying on affected Linksys devices. When devices experience performance degradation from this attack, network services may become unresponsive or significantly slowed, affecting critical operations that depend on network connectivity. The vulnerability affects a range of Linksys products including routers, access points, and other networking equipment that incorporate these specific Intel chipsets. Organizations may experience cascading effects as network outages impact downstream systems and services that rely on stable network connectivity. The attack's effectiveness is particularly concerning because it can be executed remotely without requiring authentication or specialized access privileges, making it an attractive vector for malicious actors seeking to disrupt network services.
Mitigation efforts for this vulnerability require coordination between multiple parties since Intel, as a hardware manufacturer, does not control the distribution of patches or firmware updates for the affected devices. Linksys, as the device manufacturer, must develop and distribute appropriate firmware updates to address the issue within their products. Organizations should implement network monitoring to detect unusual traffic patterns that may indicate this attack is being attempted against their systems. Network segmentation and access control measures can help limit the potential impact of such attacks by isolating critical network segments. Additionally, implementing rate limiting and packet filtering rules at network boundaries can provide some protection against the specific attack patterns associated with this vulnerability. The remediation approach must consider that hardware-level vulnerabilities often require firmware updates or chip replacements rather than simple software patches, making the mitigation process more complex and time-consuming than typical software vulnerabilities.