CVE-2023-3430

Executive Summary

CVE-2023-3430 is a heap-based buffer overflow vulnerability discovered in OpenImageIO, a widely used open-source library for reading, writing, and processing image files. The flaw resides in the GIF input handler, specifically in the src/gif.imageio/gifinput.cpp file, and can be triggered when a remote attacker supplies a specially crafted GIF image to an application that uses the library. Exploitation results in a heap buffer overflow that can crash the host application, leading to a denial of service (DoS) condition. The vulnerability carries a CVSS score of 7.5, indicating high severity, though no public proof-of-concept or in-the-wild exploitation has been observed to date. Patches have been claimed by Debian but have not been independently confirmed.

Technical Analysis

OpenImageIO is a robust, high-performance image I/O library used in visual effects, animation, and scientific computing pipelines. It provides a unified API for reading and writing images across dozens of formats, including GIF. The vulnerability is located in the GIF input parsing component, specifically within src/gif.imageio/gifinput.cpp.

The CNA title explicitly identifies the flaw as a heap-buffer-overflow in this file. Heap-based buffer overflows occur when a program writes data beyond the allocated boundary of a heap memory region. In image parsing libraries, such defects commonly arise from:

1. Insufficient bounds checking on decoded image dimensions or color table sizes — An attacker-supplied GIF file may declare image dimensions, palette entries, or frame data sizes that exceed what the parser allocates for the corresponding buffers.
2. Improper handling of malformed LZW-compressed data — GIF images use LZW compression for pixel data. A crafted file can cause the decompressor to write more output bytes than expected into the output buffer if the buffer size was computed incorrectly from headers.
3. Integer overflow in buffer size calculations — When computing buffer allocations based on width × height × bytes-per-pixel, an attacker-controlled width or height can lead to an integer wrap, resulting in a smaller allocation than required. Subsequent writes overflow the heap.

The attack surface is broad. OpenImageIO is embedded in:

• Digital content creation (DCC) tools such as Blender, Maya, and Nuke (via plugins).
• Rendering engines and texture pipelines.
• Web services that process user-uploaded images.
• Medical imaging and scientific visualization software that handles arbitrary image formats.

Because the flaw is triggered during file parsing — the earliest stage of image processing — no elevated privileges are required. The attacker only needs to deliver a malicious GIF file to the target application through any ingestion vector: a web upload endpoint, an email attachment, a network share, or a crafted file URL.

The NVD description confirms the remote attack vector and the denial-of-service outcome. It does not confirm code execution; however, heap-based buffer overflows in C++ parsing code are a recognized precursor to memory corruption that can sometimes be escalated to arbitrary code execution. Absent a proof-of-concept or detailed exploit analysis, the report treats code execution as unconfirmed but possible. The CVSS vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) confirms: network-accessible, low complexity, no privileges required, with high availability impact and no confidentiality or integrity impact.

Exploitation Scenarios

Attack Chain:

1. Reconnaissance / Target Identification: The attacker identifies an organization that processes user-supplied images. Candidates include: web applications with avatar/attachment upload features, email gateways that preview attachments, social platforms, or internal tools built on OpenImageIO (e.g., a texture-processing service, a thumbnail generator, or a batch conversion utility). The attacker may fingerprint the target by uploading a benign GIF and timing responses, or by probing for known error messages.
2. Triggering the Flaw: The attacker crafts a malicious GIF file designed to violate heap allocation assumptions in src/gif.imageio/gifinput.cpp. At the vulnerability-class level, this involves encoding frame dimensions, color table sizes, or LZW-compressed data such that the parser allocates a heap buffer smaller than the amount of data written into it.
3. Payload Execution: The crafted GIF is delivered to the target application via the chosen ingestion channel — HTTP POST to an upload endpoint, email attachment, or direct file drop. When the application parses the GIF (typically automatically during thumbnail generation, metadata extraction, or image preview), the overflow corrupts the heap.
4. Post-Exploitation Impact: The immediate effect is a crash of the parsing process, causing the application to terminate or throw an unhandled exception. In multi-tenant web environments, this can result in repeated request failures or worker process exhaustion, producing a sustained denial of service. If the heap corruption is exploited further, it could theoretically lead to arbitrary code execution within the context of the application; however, no public evidence supports this escalation for CVE-2023-3430.

Note: No public PoC is available for this vulnerability. The attack chain above is inferred from the vulnerability class and the NVD description. Specific payload structures or GIF byte-level manipulation details are not publicly documented.

Impact Assessment

CVSS Score: 7.5 (High). The vector represents: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H — network attack vector, low attack complexity, no privileges required, no user interaction, unchanged scope, no confidentiality or integrity impact, and high availability impact.

Business Impact:

• Application Availability: The most direct consequence is denial of service. Enterprise systems that rely on OpenImageIO for image processing become vulnerable to crashes when processing untrusted input. For high-availability services, this can translate into service outages, lost revenue, and degraded user experience.
• Operational Overhead: SOC and engineering teams must triage crashes, identify the malicious input, and restore services. Repeated attacks can exhaust incident-response resources.
• Potential for Escalation (unconfirmed): While the CVE only confirms DoS, heap overflows in C++ image parsers have historically led to remote code execution in other libraries (e.g., libtiff, ImageMagick). If an attacker discovers a code-execution primitive, the impact rises to full system compromise — arbitrary file read/write, lateral movement, and data exfiltration. Until mitigated, organizations should assume the worst-case is mathematically possible.
• Affected Surface: Any application linking against OpenImageIO. Given the library's use in rendering pipelines, any organization involved in media production, 3D visualization, or computer vision is at risk. The GIF format's simplicity and pervasiveness make the delivery vector trivial.

Blast Radius: The vulnerable component is a shared library. One malicious GIF can crash any process that ingests it. In microservice architectures, this could cascade if multiple services share the same codebase or library.

Detection Guidance

Detection for a heap-buffer-overflow in an image parsing library is challenging because the trigger point is internal to the library. Detection must focus on: (1) anomalous file characteristics, (2) process crashes at the parse stage, and (3) network indicators of repeated malicious uploads.

Sigma Rule

title: Suspicious GIF Upload Leading to OpenImageIO Heap Overflow
id: 8b9a3f2e-c1d4-4e8a-9f45-7d3c1a2b4e5f
status: experimental
description: Detects repeated uploads of GIF files with anomalous dimensions or size-to-dimension ratios, potentially targeting CVE-2023-3430 heap overflow in OpenImageIO.
logsource:
  category: webserver
  product: generic
detection:
  selection:
    http.method: POST
    http.content_type: image/gif
  filter_baseline:
    http.url|endswith:
      - '/icons/'
      - '/static/'
      - '/images/'
  condition: selection and not filter_baseline
  timeframe: 15m
  aggregation:
    group_by:
      - source.ip
      - http.url
    count: 10
level: medium
tags:
  - attack.t1499
  - cve.2023-3430
  - cwe.122

YARA Rule

rule CVE_2023_3430_GIF_Heap_Overflow_Indicators
{
    meta:
        author = "valtersit.com"
        description = "Detects GIF files with traits associated with heap-buffer-overflow attempts against OpenImageIO gifinput.cpp"
        cve = "CVE-2023-3430"
        severity = "medium"
    strings:
        // Screen Descriptor: 24-bit packed fields
        $gif_header = { 47 49 46 38 39 61 }  // "GIF89a"
        $gif_header_87 = { 47 49 46 38 37 61 } // "GIF87a"
        $max_width = { ?? ?? 0C 00 }          // Width field approaching 0x0C00 (3072)
        $max_height = { ?? ?? 0C 00 }         // Height field approaching
        $gct_overflow = { F? 00 }             // Global Color Table flag + size field maxed
    condition:
        ($gif_header or $gif_header_87) and
        (uint16(6) > 3000 or uint16(8) > 3000) and
        filesize < 1000
}

Suricata IDS Rule

alert http any any -> $HOME_NET any (msg:"ET EXPLOIT OpenImageIO GIF Heap Overflow Attempt (CVE-2023-3430)"; flow:to_server,established; content:"POST"; http_method; content:"image/gif"; http_client_body; pcre:"/GIF8[79]a.{0,100}\x00\x00/"; threshold:type both, track by_src, count 10, seconds 300; classtype:attempted-dos; sid:20233430; rev:1; metadata:cve CVE-2023-3430;)

Elastic Detection

sequence by host.name with maxspan=2m
  [process where event.type == "start" and process.name : "*.so" or process.name : "*openimageio*"]
  [file where event.action == "open" and file.name : "*.gif" and file.size < 1000]
  [process where event.type == "end" and process.exit_code == 139 and process.command_line : "*image*" or "*convert*"]

Splunk SPL Query

index=web sourcetype=access_combined
| search http_method=POST http_content_type="image/gif"
| eval suspicious = if(bytes > 0 AND bytes < 1000 AND uri_path LIKE "%upload%", 1, 0)
| stats count by src_ip uri_path suspicious
| where suspicious = 1 AND count > 5
| table _time src_ip uri_path count

Wazuh OSSEC Rule

<group name="openimageio,">
  <rule id="100343" level="10">
    <decoded_as>syslog</decoded_as>
    <field name="program_name">\openimageio</field>
    <regex>segfault|heap-buffer-overflow|AddressSanitizer</regex>
    <description>CVE-2023-3430: OpenImageIO heap buffer overflow — crash detected in GIF parser</description>
    <group>cve-2023-3430,</group>
  </rule>
  <rule id="100344" level="8">
    <decoded_as>syslog</decoded_as>
    <field name="program_name">\convert|\.\identify</field>
    <regex>gif</regex>
    <description>Possible OpenImageIO GIF parse crash</description>
    <group>cve-2023-3430,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch Confidence: 2/4 — CLAIMED (single source: Debian; not independently confirmed).

1) Immediate Mitigations

• Restrict Untrusted GIF Processing: If OpenImageIO is used to process user-supplied files, isolate this processing into a sandboxed, non-privileged container or restricted microservice with no network egress and limited system calls. This limits the blast radius of a crash or potential code execution.
• Static File Analysis Front-End: Before routing files to OpenImageIO, run the GIF through a lightweight pre-filter that rejects files with extreme dimensions, abnormally small file sizes for declared dimensions, or non-standard header combinations. This reduces the attack surface, though it is not a complete fix.
• Disable GIF Support in the Parser: If GIF functionality is not a business requirement, compile OpenImageIO without GIF support or disable the GIF plugin. Check the library build flags: -DUSE_GIF=OFF or equivalent for your packaging system.

2) Patch / Upgrade Steps

• Debian/Ubuntu systems: Monitor for the Debian security update (DSA) addressing CVE-2023-3430. Once released, apply immediately using apt update && apt upgrade openimageio.
• RHEL/Fedora/CentOS: Reference the Red Hat Security Advisory. Since Red Hat is the reporting party, expect an RHSA. Apply via dnf update openimageio.
• Source builds: Pull the latest OpenImageIO from the official repository and verify the fix is present in the gifinput.cpp file. Specifically, look for added bounds checks on buffer allocations for dimensions, color tables, and LZW decompression output.
• Independent verification: Since the patch is only claimed by Debian, test the patched version against the known trigger patterns before rolling out to production.

3) Long-Term Hardening

• Process Isolation: Run all file-parsing tasks in containerized environments with memory limits, CPU limits, and strict seccomp profiles. Configure resource limits so a heap overflow cannot destabilize the host.
• Memory-Safe Rewrites: For critical pipelines, evaluate dropping OpenImageIO in favor of memory-safe image libraries (e.g., Rust or Go-based alternatives) or running the parser through a memory-safe wrapper.
• Continuous Monitoring: Deploy the detection rules above across network, host, and application layers. Ensure crash events from image-processing processes are correlated with upload activity.
• Vulnerability Management: Add OpenImageIO to the organization's CVE watchlist. Track the patch claim independently and re-assess exposure once the fix is confirmed.

References

1. NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2023-3430 — Official NVD record with description, CVSS score, and reference list.
2. Red Hat CVE Database (if available): https://access.redhat.com/security/cve/CVE-2023-3430 — Vendor tracking page (Red Hat is the CNA for this advisory).
3. Debian Security Tracker: https://security-tracker.debian.org/tracker/CVE-2023-3430 — Sole source claiming patch availability; monitor for confirmation.
4. OpenImageIO GitHub Repository: https://github.com/AcademySoftwareFoundation/OpenImageIO (connection failed — verify manually) — Upstream project page; review commits and releases for fix verification, particularly in src/gif.imageio/gifinput.cpp.
5. CWE-122 Reference: https://cwe.mitre.org/data/definitions/122.html — Heap-based Buffer Overflow category description and weakness taxonomy.

Threat Actor Activity: No known threat actor campaigns or in-the-wild exploitation have been identified for CVE-2023-3430 as of this report. The EPSS score of 0.01201 reflects a low probability of exploitation in the near term, but the 65.3% percentile ranking relative to historical CVEs indicates the vulnerability class is well-understood and could attract attention once a PoC emerges. Monitor CISA KEV for updates, though the CVE is not currently listed.