The Linux kernel 4.x (starting from 4.1) and 5.x before 5.0.8 allows Information Exposure (partial kernel address disclosure), leading to a KASLR bypass. Specifically, it is possible to extract the KASLR kernel image offset using the IP ID values the kernel produces for connection-less protocols (e.g., UDP and ICMP). When such traffic is sent to multiple destination IP addresses, it is possible to obtain hash collisions (of indices to the counter array) and thereby obtain the hashing key (via enumeration). This key contains enough bits from a kernel address (of a static variable) so when the key is extracted (via enumeration), the offset of the kernel image is exposed. This attack can be carried out remotely, by the attacker forcing the target device to send UDP or ICMP (or certain other) traffic to attacker-controlled IP addresses. Forcing a server to send UDP traffic is trivial if the server is a DNS server. ICMP traffic is trivial if the server answers ICMP Echo requests (ping). For client targets, if the target visits the attacker's web page, then WebRTC or gQUIC can be used to force UDP traffic to attacker-controlled IP addresses. NOTE: this attack against KASLR became viable in 4.1 because IP ID generation was changed to have a dependency on an address associated with a network namespace.
CVSS Details
- CVSS 3.1 Base Score: 7.5
- CVSS 3.0 Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Centos_linux | — | Upgrade kernelUpgrade kernel-rt | Apr 1, 2020 | Jul 5, 2019 |
| Debian | — | Upgrade linux | Jul 26, 2019 | Jul 5, 2019 |
| F5 Big Ip | — | Update F5 BIG-IP to the latest version | Jun 17, 2026 | Aug 30, 2019 |
| Huawei Euleros 2_0_sp2 | — | Upgrade kernel-debuginfoUpgrade kernel-toolsUpgrade kernel-debug-develUpgrade perfUpgrade kernel-headersUpgrade kernel-develUpgrade kernelUpgrade kernel-debugUpgrade kernel-debuginfo-common-x86_64Upgrade python-perf | Sep 12, 2019 | Jul 5, 2019 |
| Huawei Euleros 2_0_sp3 | — | Upgrade kernelUpgrade kernel-toolsUpgrade kernel-tools-libsUpgrade kernel-debuginfo-common-x86_64Upgrade python-perfUpgrade kernel-debuginfoUpgrade kernel-headersUpgrade kernel-develUpgrade perf | Sep 25, 2019 | Jul 5, 2019 |
| Huawei Euleros 2_0_sp5 | — | Upgrade kernel-tools-libsUpgrade python-perfUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-headersUpgrade kernel-toolsUpgrade kernelUpgrade kernel-develUpgrade kernel-debuginfoUpgrade perf | Aug 16, 2019 | Jul 5, 2019 |
| Oracle_linux | — | Upgrade kernelUpgrade kernel-uek | Apr 9, 2020 | Jul 15, 2019 |
| Redhat Openshift | — | Upgrade redhat-coreos | Dec 29, 2020 | Jul 5, 2019 |
| Redhat_linux | — | No solution existsUpgrade kernelUpgrade kernel-rt | Apr 1, 2020 | Jul 5, 2019 |
| Suse | — | Upgrade kernel-source-azureUpgrade kernel-devel-azureUpgrade kernel-defaultUpgrade kernel-azure-baseUpgrade kernel-default-extraUpgrade kernel-default-manUpgrade kernel-obs-buildUpgrade kernel-docs | Jul 14, 2019 | Jul 5, 2019 |
| Ubuntu | — | Upgrade linux-image-azureUpgrade linux-image-genericUpgrade linux-image-4.15.0-60-genericUpgrade linux-image-generic-lpaeUpgrade linux-image-4.15.0-60-generic-lpaeUpgrade linux-image-virtual-hwe-16.04Upgrade linux-image-4.15.0-1043-kvmUpgrade linux-image-4.15.0-1056-azureUpgrade linux-image-aws-hweUpgrade linux-image-generic-lpae-hwe-16.04Upgrade linux-image-lowlatencyUpgrade linux-image-4.15.0-1041-gkeUpgrade linux-image-4.15.0-1044-raspi2Upgrade linux-image-4.15.0-1047-awsUpgrade linux-image-gcpUpgrade linux-image-oemUpgrade linux-image-gke-4.15Upgrade linux-image-virtualUpgrade linux-image-gkeUpgrade linux-image-awsUpgrade linux-image-4.15.0-1041-gcpUpgrade linux-image-raspi2Upgrade linux-image-oracleUpgrade linux-image-4.15.0-60-lowlatencyUpgrade linux-image-kvmUpgrade linux-image-4.15.0-1022-oracleUpgrade linux-image-lowlatency-hwe-16.04Upgrade linux-image-generic-hwe-16.04 | Sep 3, 2019 | Jul 5, 2019 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Jan 20, 2025 | Jul 5, 2019 |
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