CVE-2017-2298 in MCollective
Summary
by MITRE
The mcollective-sshkey-security plugin before 0.5.1 for Puppet uses a server-specified identifier as part of a path where a file is written. A compromised server could use this to write a file to an arbitrary location on the client with the filename appended with the string "_pub.pem".
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Analysis
by VulDB Data Team • 12/09/2022
The vulnerability identified as CVE-2017-2298 affects the mcollective-sshkey-security plugin version 0.5.1 and earlier in the Puppet infrastructure management framework. This issue represents a path traversal vulnerability that arises from the plugin's improper handling of user-supplied identifiers during file operations. The flaw occurs within the security plugin's implementation where a server-specified identifier is directly incorporated into file path construction without adequate sanitization or validation, creating a dangerous condition that allows for arbitrary file system manipulation.
The technical exploitation of this vulnerability stems from the plugin's insecure file handling practices that concatenate server-provided identifiers directly into file paths where SSH public keys are written. When a compromised server within the Puppet ecosystem executes malicious operations, it can manipulate the identifier parameter to specify arbitrary directory paths on client systems. The vulnerability specifically allows for writing files to locations outside of intended directories, with the filename being appended with the fixed string "_pub.pem". This behavior creates a potential attack vector where malicious actors can write SSH public keys to system directories or overwrite existing files, potentially compromising system integrity and user authentication mechanisms.
The operational impact of this vulnerability extends beyond simple file system manipulation to encompass broader security implications within Puppet-managed environments. Attackers who compromise a single server within the mcollective infrastructure can leverage this flaw to escalate privileges and establish persistence across multiple client systems. The vulnerability aligns with CWE-22 Path Traversal and CWE-73 Path Traversal, both of which are categorized under the broader class of insecure direct object references that allow attackers to access files and directories outside of their intended scope. This weakness can be mapped to ATT&CK technique T1059 Command and Scripting Interpreter and T1078 Valid Accounts, as it enables attackers to create malicious files that can be executed or used to maintain access to compromised systems.
The vulnerability demonstrates a critical flaw in input validation and path construction practices within the Puppet security plugin architecture. Organizations relying on mcollective-sshkey-security for managing SSH keys across their infrastructure face significant risk when using affected versions, as the compromise of any single server can potentially propagate to other systems. The attack requires only that an attacker gain access to a server within the Puppet ecosystem, making it particularly dangerous in environments where server compromise is possible through other attack vectors. The fixed version 0.5.1 addresses this issue by implementing proper path sanitization and validation, ensuring that user-supplied identifiers cannot be used to manipulate file paths outside of designated directories. Organizations should immediately upgrade to the patched version and conduct thorough security assessments of their Puppet environments to identify any potential exploitation attempts or lingering effects from compromised systems.