CVE-2018-5899 in Android
Summary
by MITRE
In Android releases from CAF using the linux kernel (Android for MSM, Firefox OS for MSM, QRD Android) before security patch level 2018-06-05, whenever TDLS connection is setup, we are freeing the netbuf in ol_tx_completion_handler and after that, we are accessing it in NBUF_UPDATE_TX_PKT_COUNT causing a use after free.
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Analysis
by VulDB Data Team • 02/26/2020
The vulnerability described in CVE-2018-5899 represents a critical use-after-free condition within the Android kernel's wireless networking stack, specifically affecting devices utilizing the Qualcomm Android for MSM, Firefox OS for MSM, and QRD Android platforms. This flaw exists in kernel versions prior to the security patch level 2018-06-05 and stems from improper memory management during wireless data transmission processes. The vulnerability manifests when establishing TDLS (Tunneled Direct Link Setup) connections, which are used to create direct communication links between wireless devices without routing through the access point.
The technical flaw occurs in the wireless driver's transmission completion handling mechanism where the network buffer object is prematurely freed within the ol_tx_completion_handler function. Subsequently, the same freed buffer is accessed in the NBUF_UPDATE_TX_PKT_COUNT function, creating a classic use-after-free scenario that can lead to arbitrary code execution or system instability. This memory management error falls under CWE-416, which specifically addresses the use of freed memory conditions in software development. The vulnerability demonstrates a fundamental flaw in the driver's resource management where the same memory location is accessed after being deallocated, violating the principle of proper memory lifecycle management.
The operational impact of this vulnerability is significant as it can be exploited by malicious actors to gain unauthorized access to affected devices or cause denial of service conditions. An attacker positioned within the wireless network's range could potentially establish a TDLS connection and trigger the use-after-free condition, leading to privilege escalation or complete system compromise. The vulnerability affects a wide range of Android devices including smartphones, tablets, and other wireless-enabled platforms that utilize Qualcomm's MSM (Mobile Station Modem) chipsets. This represents a critical security risk for enterprise environments where wireless networks are extensively deployed and where wireless device security is paramount.
Mitigation strategies for CVE-2018-5899 primarily involve applying the security patch released by Google on June 5, 2018, which addresses the memory management issue in the wireless driver's TDLS implementation. Organizations should prioritize patch deployment across all affected devices and monitor for any signs of exploitation attempts. Additionally, network administrators should implement wireless network segmentation and monitoring to detect potential exploitation attempts. The vulnerability also aligns with ATT&CK technique T1059, which involves the execution of malicious code through system vulnerabilities, and T1068, which covers the exploitation of local system privileges. Regular security assessments and kernel integrity checks should be implemented to prevent exploitation of similar memory corruption vulnerabilities in the wireless subsystem.