Cybersecurity professionals consider CVE-2017-4995 an immediate threat requiring urgent mitigation.
Status: Modified
Last updated: 🕒 21 Nov 2024, 03:26 UTC
Originally published on: 🕙 27 Nov 2017, 10:29 UTC
Time between publication and last update: 2550 days
CVSS Release: version 3
nvd@nist.gov
Primary
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CVE-2017-4995: An issue was discovered in Pivotal Spring Security 4.2.0.RELEASE through 4.2.2.RELEASE, and Spring Security 5.0.0.M1. When configured to enable default typing, Jackson contained a deserialization vulnerability that could lead to arbitrary code execution. Jackson fixed this vulnerability by blacklisting known "deserialization gadgets." Spring Security configures Jackson with global default typing enabled, which means that (through the previous exploit) arbitrary code could be executed if all of the following is true: (1) Spring Security's Jackson support is being leveraged by invoking SecurityJackson2Modules.getModules(ClassLoader) or SecurityJackson2Modules.enableDefaultTyping(ObjectMapper); (2) Jackson is used to deserialize data that is not trusted (Spring Security does not perform deserialization using Jackson, so this is an explicit choice of the user); and (3) there is an unknown (Jackson is not blacklisting it already) "deserialization gadget" that allows code execution present on the classpath. Jackson provides a blacklisting approach to protecting against this type of attack, but Spring Security should be proactive against blocking unknown "deserialization gadgets" when Spring Security enables default typing.
The exploitability of CVE-2017-4995 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-2017-4995 presents a challenge to exploit due to its high attack complexity, but the absence of privilege requirements still makes it a viable target for skilled attackers. A thorough security review is advised.
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-2017-4995, 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-2017-4995, 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: 0.508% (probability of exploit)
EPSS Percentile: 76.79%
(lower percentile = lower relative risk)
This vulnerability is less risky than approximately 23.209999999999994% of others.
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