CVE-2017-15235 : Detail

CVE-2017-15235

7.5
/
High
Authorization problems
A01-Broken Access Control
16.75%V4
Network
2017-10-11
01h00 +00:00
2020-08-29
19h06 +00:00
CVE.org
NVD
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CVE Descriptions

The File Manager (gollem) module 3.0.11 in Horde Groupware 5.2.21 allows remote attackers to bypass Horde authentication for file downloads via a crafted fn parameter that corresponds to the exact filename.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-425 Direct Request ('Forced Browsing')
The web application does not adequately enforce appropriate authorization on all restricted URLs, scripts, or files.

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.
EPSS First.org

Exploit information

Exploit Database EDB-ID : 44059

Publication date : 2017-08-02 22h00 +00:00
Author : SecuriTeam
EDB Verified : No

## Vulnerability Summary The following advisory describes an unauthorized file download vulnerability found in Horde Groupware version 5.2.21. Horde Groupware Webmail Edition is “a free, enterprise ready, browser based communication suite. Users can read, send and organize email messages and manage and share calendars, contacts, tasks, notes, files, and bookmarks with the standards compliant components from the Horde Project. Horde Groupware Webmail Edition bundles the separately available applications IMP, Ingo, Kronolith, Turba, Nag, Mnemo, Gollem, and Trean.” ## Credit An independent security researcher, Juan Pablo Lopez Yacubian, has reported this vulnerability to Beyond Security’s SecuriTeam Secure Disclosure program. ## Vendor response Horde Groupware was informed of the vulnerability, to which they response with: “this has already been reported earlier by someone else, and is already fixed in the latest Gollem and Horde Groupware releases. Besides that, it’s not sufficient to have a list of the server’s users, you also need to exactly know the file name and path that you want to download. Finally, this only works on certain backends, where Horde alone is responsible for authentication, i.e. it won’t work with backends that require explicit authentication.” CVE: CVE-2017-15235 ## Vulnerability details User controlled input is not sufficiently sanitized when passed to File Manager (gollem) module (version 3.0.11). The “fn” parameter does not validate certain met characters by causing the requested file or filesystem to be downloaded without credentials. It is only necessary to know the username and the file name. ## Proof of Concept ``` User = this is the username in horde / = the Meta character / /services/download/?app=gollem&dir=%2Fhome%2Fuser&backend=sqlhome&fn=/test.php ```

Products Mentioned

Configuraton 0

Horde>>Groupware >> Version 5.2.21

References