CVE-2022-2979

Executive Summary

CVE-2022-2979 is a memory-management vulnerability in Omron CX-Programmer, a Windows-based programming environment used to configure and maintain Omron programmable logic controllers (PLCs). The flaw is triggered when a user opens a specially crafted file, causing the application to fail to release memory references properly, which could ultimately lead to arbitrary code execution on the host workstation. Successful exploitation requires social engineering or another mechanism to induce an administrator or engineer to open a malicious file, making this a client-side attack vector with high confidentiality, integrity, and availability impact (CVSS 7.8). Organizations operating Omron CX-Programmer in their ICS/OT environments should prioritize updating to version 9.78 and implementing user-awareness training.

Technical Analysis

The vulnerability is rooted in improper memory reference management within Omron CX-Programmer. According to the NVD description, opening a "specially crafted file" causes the product to fail to release its memory reference. This class of vulnerability is categorized under CWE-401 (Improper Release of Memory Before Removing Last Reference) — commonly described as a memory leak. However, the practical security impact extends beyond resource exhaustion: in this case, the description explicitly states that the flaw "could potentially result in arbitrary code execution."

From a technical standpoint, a failure to release memory references in a complex application like a PLC programming suite can manifest in multiple ways. The most likely mechanism involves object lifetime mismanagement — the application may use a heap-based object after a reference count has become inconsistent, leading to a type confusion or use-after-free scenario. Alternatively, the memory leak itself may allow an attacker to influence heap layout spray-and-pray style exploitation, where subsequent allocations return predictable addresses containing attacker-controlled data, which can then be interpreted as function pointers.

At the vulnerability-class level, CWE-401 issues in desktop applications frequently emerge from broken cleanup paths in parser code. When CX-Programmer parses project files (e.g., .cxp project archives or related file formats), it allocates objects for each structural element. A crafted file can cause one of these allocation paths to register a reference in a management structure while deliberately omitting the corresponding cleanup code, or vice versa. Over successive processed elements, the reference table becomes corrupted, and when the application later tries to dereference entries from that table during a cleanup or export operation, it may execute code at an attacker-controlled memory offset.

It is important to note that the NVD description is sparse — no specific function names, file extensions, or parse paths have been disclosed. The exploitation mechanism is described generically as "arbitrary code execution" via memory reference failure. The attack surface is the CX-Programmer file parsing subsystem, reachable by enticing a user to open a malicious file via email, USB drive, or a shared network folder — a common vector in OT environments.

Exploitation Scenarios

The attack chain for CVE-2022-2979 is inferred from the vulnerability class and available intelligence. No public PoC or exploit code has been disclosed at the time of writing; the attack chain below is derived strictly from the NVD description and standard client-side exploitation techniques.

1. Reconnaissance and Targeting: An adversary targeting an industrial automation environment must first identify organizations that use Omron CX-Programmer. Reconnaissance may include searching for employees via LinkedIn or job boards for firms that list Omron PLC experience, or scanning for exposed engineering workstations. Alternatively, attackers may use supply-chain tactics, compromising an MES or document-sharing platform where engineering tooling is exchanged.

2. Triggering the Flaw: The attacker crafts a malicious file designed to exploit the memory reference failure. Because CX-Programmer is a project-file–centric application, the malicious file is most plausibly a project archive that appears legitimate, possibly with a matching icon and naming convention (e.g., a "modified project" or "vendor update"). The victim must open this file using the affected software — via double-clicking, File → Open, or drag-and-drop — which activates the vulnerable parsing logic.

3. Payload Execution: At the vulnerability-class level, the payload would be embedded in the crafted file such that when the memory reference failure occurs, the application's control flow is redirected to attacker-controlled data (e.g., shellcode within the file). Given that CWE-401 leads to arbitrary code execution, the attacker likely manipulates heap layout to overwrite a function pointer or return address with a pointer to a ROP chain or injected code. On a typical engineering workstation running with administrative privileges (common in OT environments), this would grant the attacker a SYSTEM or admin-level shell.

4. Post-Exploitation: Once code execution is achieved, the attacker can leverage the compromised workstation as a pivot point into the OT network. From a Windows engineering station, an attacker may:

   • Install persistence via scheduled tasks, service creation, or registry modifications.
   • Harvest credentials from credential vaults or cached sessions.
   • Use the workstation's existing HMI/SCADA connections to send malicious commands to connected PLCs.
   • Deploy additional offensive tools (e.g., Cobalt Strike lateral movement) targeting the OT network segment.

No public PoC is available; the attack chain is inferred from the vulnerability class and the explicit "arbitrary code execution" claim in the NVD description.

Impact Assessment

Business Impact: Successful exploitation of this vulnerability can lead to the complete compromise of engineering workstation and, by extension, manipulation of production-line logic. In severe cases, an attacker could alter machine safety routines or cause unplanned shutdowns, resulting in significant production downtime, equipment damage, or safety incidents. The requirement for user interaction (opening a file) somewhat reduces the risk of mass exploitation but increases the risk to specific targeted assets.

Detection Guidance

The following detection rules are theoretical and designed to identify potential exploitation attempts based on the vulnerability's characteristics. Since CX-Programmer is a local desktop application with no network component, detection focuses on file-based indicators and post-exploitation behavior.

Sigma Rule

title: Potential CVE-2022-2979 CX-Programmer Malicious File Execution
id: 7a3c9f21-9b7e-4d2c-8f8a-5b1e2a3c4d5e
status: experimental
description: Detects suspicious file opens or CX-Programmer processes crashing subsequent to opening a file, indicative of CVE-2022-2979 exploitation.
author: Valters IT Security
date: 2024/01/15
logsource:
    category: process_creation
    product: windows
detection:
    selection_process:
        Image|endswith:
            - '\cxp.exe'
            - '\cx-programmer.exe'
            - '\cxprog.exe'
    selection_behavior:
        CommandLine|contains:
            - '.cxp'
            - '.opt'
            - '.xsd'
    filter_users:
        User|contains:
            - 'SYSTEM'
            - 'NETWORK SERVICE'
    condition: selection_process and selection_behavior and not filter_users
level: medium
falsepositives:
    - Legitimate engineers opening project files on a regular basis
    - Automated build processes that invoke CX-Programmer CLI
tags:
    - attack.execution
    - attack.t1203
    - cve.2022-2979

YARA Rule

rule CVE_2022_2979_Omron_CX_Programmer_CraftFile
{
    meta:
        author = "Valters IT Security"
        description = "YARA rule detecting potentially malicious CX-Programmer project files crafted to exploit CVE-2022-2979"
        date = "2024-01-15"
        reference = "CVE-2022-2979"
        score = 60
    strings:
        $mx_omron = "OMRON" ascii wide
        $mx_fileid = "CX-Programmer" ascii wide
        $mx_overlong = {FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF}
        $mx_leakptr = {F0 ?? ?? ?? ?? F4 ?? ?? ?? ??}
    condition:
        uint16(0) == 0x4D5A and 2 of ($mx_*) and filesize < 10MB and $mx_overlong
}

Suricata IDS Rule

alert tcp any any -> any any (msg:"CVE-2022-2979 Potential CX-Programmer Malicious File Transfer"; content:"CX-Programmer"; nocase; content:".cxp"; nocase; within:200; flow:established,to_server; classtype:attempted-user; sid:20229790; rev:1; metadata:created_at 2024_01_15, updated_at 2024_01_15, cve 2022-2979;)

Note: Because this vulnerability requires local file opening, network detection is limited to file transfer stages (SMB, HTTP downloads). The rule above is illustrative and would require tuning for your network's file-transfer patterns.

Elastic Detection

// EQL rule for detecting CX-Programmer process crashes or abnormal exit after opening file
sequence by process.entity_id with maxspan=10m
    [process where event.type == "start" and process.name : "cx*.exe" and process.args : ("*.cxp", "*.opt")]
    [process where event.type == "end" and process.exit_code > 0 and process.name : "cx*.exe"]

Splunk SPL Query

index=windows sourcetype=WinEventLog:Security OR source="XmlWinEventLog:Microsoft-Windows-Sysmon/Operational"
(EventCode=1 AND Image="*\\cxp.exe") 
| rex field=CommandLine "(?<file_extension>\.(cxp|opt)$)"
| where isnotnull(file_extension)
| join type=inner process_id
    [ search index=windows sourcetype=WinEventLog:Application EventCode=1000
    | rename "EventData.Image" as Image
    | search Image="*cxp*"
    | eval crash_frametime = _time
    | fields process_id, crash_frametime]
| eval crash_within_5min = if((crash_frametime - _time) < 300, "yes", "no")
| search crash_within_5min="yes"
| stats count by host, user, CommandLine, file_extension

Wazuh OSSEC Rule

<group name="omron_CX_programmer,">
    <rule id="297902" level="10">
        <if_sid>550</if_sid>  <!-- program executed -->
        <regex>cxp\.exe|\bcx-programmer\b</regex>
        <description>CVE-2022-2979 - Omron CX-Programmer executed with potential malicious file reference - possible exploitation</description>
        <group>cve_2022_2979,</group>
        <mitre>
            <id>T1203</id>
        </mitre>
        <options>no_full_log</options>
    </rule>

    <rule id="297903" level="12">
        <if_sid>297902</if_sid>
        <regex>\.cxp\W|\.opt\W|\.xsd\W</regex>
        <description>CVE-2022-2979 - CX-Programmer opened project file with potentially crafted extension - high risk</description>
        <group>cve_2022_2979,</group>
        <mitre>
            <id>T1203</id>
        </mitre>
    </rule>
</group>

Mitigation & Patch Guidance

Patch Confidence: 2/4 (CLAIMED) — The vendor (CNA) asserts a patch is available in CX-Programmer v9.78; this claim has not been independently confirmed by third-party research or exploit testing.

Immediate Mitigations

1. Restrict file access: Implement application allowlisting (e.g., AppLocker, WDAC) to prevent CX-Programmer from executing from non-standard paths or interacting with files outside designated project directories.
2. Email and web filtering: Block or sandbox suspicious attachments, particularly file types commonly used with PLC programming tools (e.g., .cxp archives, .zip containing project files).
3. User awareness: Instruct all engineering personnel to not open unexpected project files from unverified sources, regardless of sender identity. Verify file hashes externally before opening.
4. Least privilege: Ensure engineering workstations operate with non-admin accounts. CX-Programmer does not require local admin rights for standard operation.
5. Endpoint protection: Deploy EDR/AV with behavioral detection and enable memory-protection features (e.g., exploit guard settings).
6. Network segmentation: Ensure engineering workstations are not reachable directly from the internet and only accessible via VPN/jump host.

Patch / Upgrade Steps

1. Contact Omron or access the Omron support portal to obtain the latest CX-Programmer installer.
2. Back up any existing project files, symbol tables, and configuration data.
3. Uninstall the existing CX-Programmer version.
4. Install CX-Programmer v9.78.
5. Re-import existing projects and confirm PLC communication integrity.
6. Verify the installation hash against the official checksum provided by Omron.

Long-Term Hardening

1. Establish a patch-management cadence for all OT-adjacent software, not just PLC firmware.
2. Use a dedicated "engineering network" VLAN with strict egress controls; engineering tools should not reach the internet.
3. Deploy centralized logging of file executions and process crashes (e.g., Sysmon on engineering stations).
4. Implement regular vulnerability scanning of OT endpoints using tools that identify known CVEs in installed software.
5. Develop an incident response playbook for suspected OT workstation compromise, including forensic preservation of the engineering workstation and PLC program integrity checks.

References

1. NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2022-2979
2. Omron Advisory (vendor CNA): https://www.omron.com/global/en/ (referencing CX-Programmer v9.78 update)
3. CVE Details: https://www.cvedetails.com/cve/CVE-2022-2979/
4. MITRE ATT&CK — T1203 Exploitation for Client Execution: https://attack.mitre.org/techniques/T1203/
5. CISA ICS-CERT Advisories (general OT guidance): https://www.cisa.gov/ics

Known Threat Actor Campaigns: None identified at the time of writing. CISA KEV listing is absent, EPSS percentile is low (14.7%), and no exploit-in-the-wild evidence has been published. The threat landscape for this CVE is currently latent; however, given the criticality of OT environments, targeted attacks cannot be ruled out if the vulnerable software is exposed to untrusted file inputs.