Cybersecurity professionals consider CVE-2015-8542 an immediate threat requiring urgent mitigation.
Status: Modified
Last updated: 🕝 21 Nov 2024, 02:38 UTC
Originally published on: 🕡 15 Dec 2016, 06:59 UTC
Time between publication and last update: 2897 days
CVSS Release: version 3
nvd@nist.gov
Primary
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVE-2015-8542: An issue was discovered in Open-Xchange Guard before 2.2.0-rev8. The "getprivkeybyid" API call is used to download a PGP Private Key for a specific user after providing authentication credentials. Clients provide the "id" and "cid" parameter to specify the current user by its user- and context-ID. The "auth" parameter contains a hashed password string which gets created by the client by asking the user to enter his or her OX Guard password. This parameter is used as single point of authentication when accessing PGP Private Keys. In case a user has set the same password as another user, it is possible to download another user's PGP Private Key by iterating the "id" and "cid" parameters. This kind of attack would also be able by brute-forcing login credentials, but since the "id" and "cid" parameters are sequential they are much easier to predict than a user's login name. At the same time, there are some obvious insecure standard passwords that are widely used. A attacker could send the hashed representation of typically weak passwords and randomly fetch Private Key of matching accounts. The attack can be executed by both internal users and "guests" which use the external mail reader.
The exploitability of CVE-2015-8542 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
CVE-2015-8542 presents an accessible attack vector with minimal effort required. Restricting access controls and implementing security updates are critical to reducing exploitation risks.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2015-8542, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2015-8542, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
The EPSS score estimates the probability that this vulnerability will be exploited in the near future.
EPSS Score: 0.205% (probability of exploit)
EPSS Percentile: 59.0%
(lower percentile = lower relative risk)
This vulnerability is less risky than approximately 41.0% of others.
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