UBUNTU-CVE-2019-10639
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.
02 / AFFECTED SOFTWARE
Affected packages
61 explicit affected versions
24 explicit affected versions
191 explicit affected versions
29 explicit affected versions
11 explicit affected versions
1 explicit affected versions
34 explicit affected versions
1 explicit affected versions
1 explicit affected versions
12 explicit affected versions
1 explicit affected versions
29 explicit affected versions
1 explicit affected versions
11 explicit affected versions
34 explicit affected versions
10 explicit affected versions
28 explicit affected versions
1 explicit affected versions
7 explicit affected versions
23 explicit affected versions
11 explicit affected versions
63 explicit affected versions
30 explicit affected versions
35 explicit affected versions
91 explicit affected versions
51 explicit affected versions
42 explicit affected versions
1 explicit affected versions
1 explicit affected versions
50 explicit affected versions
12 explicit affected versions
30 explicit affected versions
26 explicit affected versions
27 explicit affected versions
75 explicit affected versions
55 explicit affected versions
5 explicit affected versions
21 explicit affected versions
11 explicit affected versions
1 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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.
05 / REFERENCES