CVE-2017-18225 in jabberd2
Summary
by MITRE
The Gentoo net-im/jabberd2 package through 2.6.1 installs jabberd, jabberd2-c2s, jabberd2-router, jabberd2-s2s, and jabberd2-sm in /usr/bin owned by the jabber account, which might allow local users to gain privileges by leveraging access to this account and then waiting for root to execute one of these programs.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 01/12/2020
The CVE-2017-18225 vulnerability resides within the Gentoo net-im/jabberd2 package version 2.6.1 and earlier, presenting a significant local privilege escalation risk through improper file ownership and execution privileges. This vulnerability specifically affects the jabberd2 package installation process where multiple executable binaries including jabberd, jabberd2-c2s, jabberd2-router, jabberd2-s2s, and jabberd2-sm are installed in the /usr/bin directory with ownership assigned to the dedicated jabber system account. The flaw stems from the package maintainer's decision to grant the jabber user ownership over these critical binaries, creating a potential attack vector for privilege escalation.
The technical exploitation of this vulnerability relies on the principle of least privilege violation and improper privilege management. When a local attacker gains access to the jabber account through various means such as password compromise, social engineering, or other initial access vectors, they can manipulate the environment to execute malicious code within the context of these binaries. The vulnerability becomes particularly dangerous because root typically executes these programs during normal system operations, creating an opportunity for privilege elevation when the attacker can influence the execution flow. This represents a classic case of privilege escalation through file ownership manipulation and execution contexts.
From an operational impact perspective, this vulnerability allows attackers to escalate privileges from the jabber user level to root level without requiring additional authentication mechanisms or complex exploitation techniques. The attack surface is broad as it affects multiple components of the jabberd2 service architecture, making it a particularly attractive target for attackers seeking persistent access. The vulnerability is especially concerning in environments where the jabber service is actively used, as root execution of these binaries occurs regularly, increasing the window of opportunity for exploitation. This flaw directly violates the principle of least privilege and creates a persistent backdoor for privilege escalation attacks.
The vulnerability aligns with CWE-276, which addresses improper file permissions and ownership, and represents a specific implementation of improper privilege management. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques, specifically leveraging file permissions and execution contexts. The attack requires initial access to the jabber account, which may be achieved through various initial access methods including credential compromise, weak password policies, or other account compromise techniques. The exploitation process involves waiting for root to execute one of the vulnerable binaries, which can be accomplished through various timing and environmental manipulation techniques.
Recommended mitigations for CVE-2017-18225 include immediate package updates to versions that properly address the file ownership issue, ensuring that binaries are owned by root or appropriate system accounts rather than the jabber user. System administrators should implement strict file permission controls and regularly audit binary ownership and permissions within the system. The package maintainers should ensure that security-conscious default installations are implemented, avoiding unnecessary privilege escalation opportunities. Additionally, monitoring and logging of execution contexts for these binaries should be implemented to detect potential exploitation attempts. Organizations should also consider implementing privilege separation and least privilege principles for all system accounts, ensuring that no user account has unnecessary ownership over critical system binaries that may be executed with elevated privileges by root processes.