CVE-2018-6537 in SyncBreeze Enterprise
Summary
by MITRE
A buffer overflow vulnerability in the control protocol of Flexense SyncBreeze Enterprise v10.4.18 allows remote attackers to execute arbitrary code by sending a crafted packet to TCP port 9121.
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Analysis
by VulDB Data Team • 01/01/2020
The vulnerability identified as CVE-2018-6537 represents a critical buffer overflow flaw within the control protocol implementation of Flexense SyncBreeze Enterprise version 10.4.18. This issue manifests as a classic stack-based buffer overflow that occurs when the application processes incoming network packets on TCP port 9121, which serves as the primary control interface for the synchronization service. The flaw arises from insufficient input validation and bounds checking within the protocol handler, allowing malicious actors to craft specially formatted packets that exceed the allocated buffer space and overwrite adjacent memory regions. The vulnerability specifically affects the enterprise version of SyncBreeze, which is designed for large-scale file synchronization and management across networked environments, making it a prime target for attackers seeking to compromise critical infrastructure.
The technical exploitation of this vulnerability follows established patterns consistent with CWE-121, which catalogs buffer overflow conditions where insufficient bounds checking allows memory corruption. Attackers can leverage this flaw by sending malicious packets that contain oversized data payloads to the designated TCP port 9121, triggering the buffer overflow condition that can lead to arbitrary code execution. The remote nature of this vulnerability eliminates the need for local system access, enabling attackers to compromise systems from external network positions. The control protocol implementation appears to lack proper input sanitization mechanisms, allowing attackers to manipulate memory layout and potentially redirect execution flow through stack corruption. This type of vulnerability falls under the ATT&CK technique T1203, which describes exploitation of software vulnerabilities for remote code execution, making it particularly dangerous in enterprise environments where such services are often exposed to untrusted networks.
The operational impact of CVE-2018-6537 extends beyond simple remote code execution, as it provides attackers with persistent access to affected systems and potentially enables lateral movement within networked environments. Organizations running SyncBreeze Enterprise on exposed TCP port 9121 face significant risk of complete system compromise, as the vulnerability allows attackers to execute arbitrary commands with the privileges of the running service. The affected service typically operates with elevated permissions to manage file synchronization tasks, meaning successful exploitation could provide attackers with administrative access to the underlying system. Additionally, the vulnerability's presence in enterprise-grade software increases the potential for widespread impact across multiple systems within an organization, particularly in environments where multiple SyncBreeze instances are deployed across different network segments. The lack of authentication requirements for the control protocol further amplifies the risk, as attackers can exploit the vulnerability without needing valid credentials.
Mitigation strategies for this vulnerability require immediate action to address the root cause through proper input validation and bounds checking within the application's network protocol handler. Organizations should implement network segmentation to restrict access to TCP port 9121, ensuring that only trusted internal systems can reach this control interface. The most effective immediate solution involves applying the vendor-provided patch or upgrade to a version that addresses the buffer overflow condition, as Flexense likely released a security update to resolve this issue. Network-based mitigations such as firewall rules can temporarily restrict access to the vulnerable port, while IDS/IPS signatures should be deployed to detect and block malicious packet patterns targeting this specific vulnerability. System administrators should also consider implementing monitoring solutions to detect unusual network activity on port 9121, as abnormal packet sizes or malformed data could indicate exploitation attempts. The vulnerability highlights the importance of secure coding practices and input validation, particularly for network-facing services, and serves as a reminder of the critical need for regular security assessments and vulnerability management processes that can identify and remediate such conditions before they can be exploited by malicious actors.