Ocularis Recorder VMS_VA Denial of Service Vulnerability

OVERVIEW

Talos is disclosing a denial-of-service vulnerability in the Ocularis Recorder. Ocularis is a video management software (VMS) platform used in a variety of settings, from convenience stores, to city-wide deployments. An attacker can trigger this vulnerability by crafting a malicious network packet that causes a process to terminate, resulting in a denial of service.

DETAILS

An exploitable denial-of-service vulnerability exists in the Ocularis Recorder functionality of Ocularis 5.5.0.242. A specially crafted TCP packet can cause a process to terminate, resulting in denial of service.

The VMS_VA server process is listening for incoming TCP connections on a port in the range of 60801-65535. When a client connects to it and sends any unexpected data, the binary will respond with «Hello World!» The binary has a check to see if the receiving data starts with «dispose.” If it does, the server process kills itself. There is no authentication required for this command to go through. Any attacker with network access to the server application can use this to execute a denial-of-service attack.


Ocularis Recorder VMS_VA Denial of Service Vulnerability

JUNE 5, 2018 CVE NUMBER CVE-2018-3852

Summary

An exploitable denial of service vulnerability exists in the Ocularis Recorder functionality of Ocularis 5.5.0.242. A specially crafted TCP packet can cause a process to terminate resulting in denial of service. An attacker can send a crafted TCP packet to trigger this vulnerability.

Tested Versions

Ocularis Recorder 5.5.0.242

Product URLs

https://onssi.com/

CVSSv3 Score

7.5 — CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE

CWE-250 — Execution with Unnecessary Privileges

Details

This binary listens for incoming TCP connections. When a client connects to this binary and sends any non expected data, the binary will respond with «Hello World!». If the server receives the dispose command it will terminate the VMS_VA process.

this.tcpListener = new TcpListener(IPAddress.Any, 60801 + ConfigID);
Thread thread = new Thread(new ThreadStart(this.ListenForClients))
{
    Name = "VA CommServer V4 Listener"
};
..........
if (str.StartsWith("dispose"))
{
    this.Running = false;
    bytes = Encoding.Default.GetBytes("Ack!");
}

The binary has a check to see if the receiving data starts with «dispose». If it does the «this.Running» variable will be set to false which results in the process killing itself. There is no authentication required for this command to go through.

Crash Information

N/A

Exploit Proof-of-Concept

$ echo "dispose" | nc -nv 192.168.56.102 60801
192.168.56.102 60801 open
Ack!

Mitigation

This vulnerability can be mitigated by not allowing VMS_VA.exe from accepting inbound connections. It is unclear if this will have any adverse affect on the Ocularis Recorder module as the product documentation explicitly states to allow inbound traffic to this binary.

Timeline

2018-03-05 — Vendor Disclosure
2018-06-04 — Public Release


 

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