CVE-2023-23958

Executive Summary

CVE-2023-23958 is a Hash Leak vulnerability affecting Symantec Protection Engine (SPE) versions prior to 9.1.0. The flaw allows an unauthenticated remote attacker to extract sensitive hash values from the affected system, potentially enabling further credential-based attacks or information disclosure.

The vulnerability carries a CVSS score of 6.8 (Medium severity) and has a low EPSS score of 0.00515, indicating limited current exploitation activity. No public PoC, exploit code, or Nuclei template exists to date, and the vulnerability is not listed in CISA's Known Exploited Vulnerabilities catalog.

Technical Analysis

The NVD description for CVE-2023-23958 is notably sparse, indicating only that "Symantec Protection Engine, prior to 9.1.0, may be susceptible to a Hash Leak vulnerability." No CWE classification, detailed CVSS vector, or technical breakdown is provided in the official description.

Vulnerability Class: The "Hash Leak" vulnerability class generally refers to a condition where an application discloses cryptographic hash values (such as password hashes, session tokens, or checksums) to unauthorized parties. In the context of a security scanning product like Symantec Protection Engine, this could involve:

1. Information Disclosure via Application Response: The application may return hash values in error messages, debug responses, or unauthenticated API responses.
2. Weak Cryptographic Implementation: The product may use weak hashing algorithms or fail to properly protect hash values in transit or at rest.
3. Access Control Bypass: An attacker may leverage the leaked hashes to bypass authentication mechanisms or impersonate legitimate users.

Attack Surface: Symantec Protection Engine is typically deployed as a content-scanning component within enterprise environments, often exposed to network traffic for malware detection. The product's default listening interfaces and scanning capabilities represent the primary attack surface. As a prior-to-9.1.0 version vulnerability, any network-exposed instance of SPE is theoretically susceptible.

Affected Systems: All deployments of Symantec Protection Engine prior to version 9.1.0 are potentially affected. The product is commonly integrated into mail gateways, web proxies, and other network security infrastructure.

Note: Insufficient technical detail is available in the provided CVE description to specify exact vulnerable functions, endpoints, or code paths. This analysis is based on the vulnerability class as described.

Exploitation Scenarios

Based strictly on the NVD description and available data, the attack chain is hypothesized as follows:

1. Reconnaissance/Target Identification: An attacker identifies a network-exposed Symantec Protection Engine instance. This may be accomplished via network scanning for known service ports associated with the product or through Shodan-style documentation searching.

2. Triggering the Flaw: The attacker sends a crafted request to the SPE application designed to elicit an error response or debug output that includes internal hash values. Given the "Hash Leak" description, the flaw likely resides in an unauthenticated request handling path that improperly returns hashed data in responses.

3. Payload/Execution Method: At the vulnerability-class level, the attacker exploits the improper disclosure by either:

   • Sending malformed requests that trigger verbose error messages containing hash data.
   • Accessing diagnostic or status endpoints that expose internal hash values without authentication.

4. Post-Exploitation Impact: Successfully extracting hash values may allow the attacker to:

   • Perform offline password cracking attempts against recovered hashes.
   • Use leaked session or authentication tokens to access privileged functionality.
   • Gather reconnaissance data that aids in further attacks against the underlying infrastructure.

No public PoC is available; this attack chain is inferred from the vulnerability class and standard exploitation patterns for information disclosure flaws.

Impact Assessment

CVSS Analysis: The vulnerability is scored at 6.8 out of 10 (Medium severity). While the exact vector is not provided, the score suggests a network-exploitable condition with elevated confidentiality impact. The low EPSS score (0.00515, 41.3rd percentile) indicates that this vulnerability is not currently a primary target for threat actors in the wild.

Business Impact: For organizations running Symantec Protection Engine in production environments, successful exploitation could result in:

• Confidentiality Loss: Exposure of sensitive hash values that may relate to internal credentials or system secrets.
• Credential Compromise: If leaked hashes are crackable, an attacker may gain unauthorized access to protected systems.
• Reputational Damage: A security product being compromised undermines customer trust and may trigger regulatory reporting obligations.

Blast Radius: The impact is limited to the SPE instance and any downstream systems whose credentials or data pass through it. Because SPE is often deployed in security-critical paths, a compromise could potentially affect the integrity of the broader security infrastructure. However, the lack of confirmed exploit activity suggests the real-world impact remains theoretical at this stage.

Detection Guidance

Sigma Rule

title: Symantec Protection Engine Hash Leak Attempt
id: 0f5c7a2e-8b9d-4c34-9f02-1da2b4e5c6f7
status: experimental
description: Detects potential exploitation attempts against CVE-2023-23958 hash leak vulnerability
logsource:
  category: webserver
  product: symantec
detection:
  selection_errors:
    status: 5*|4*
    body|contains:
      - 'hash'
      - 'md5'
      - 'sha1'
      - 'token'
      - 'credential'
  selection_requests:
    http_method: GET|POST
    uri|contains:
      - 'debug'
      - 'diagnostic'
      - 'status'
      - 'error'
  condition: selection_errors and selection_requests
level: medium
falsepositives:
  - Legitimate administrative access to diagnostic endpoints
  - Normal error handling that includes hash references

YARA Rule

rule Symantec_Protection_Engine_Hash_Leak {
    meta:
        author = "Valtersit Threat Research"
        description = "Detects potential hash leak exploitation payloads targeting Symantec Protection Engine"
        cve = "CVE-2023-23958"
        date = "2023-11-01"
        severity = "medium"
    strings:
        $hash_reference = /(md5|sha1|sha256|hash)[=:]\s*[a-f0-9]{32,64}/i
        $debug_endpoint = /(debug|diagnostic|trace|status).*?(hash|token|credential)/i
        $response_header = "X-Symantec"
    condition:
        any of ($hash_reference, $debug_endpoint) and filesize < 5KB
}

Suricata IDS Rule

alert http any any -> $HOME_NET any (msg:"Symantec Protection Engine Hash Leak Attempt (CVE-2023-23958)"; flow:established,to_server; content:"GET"; http_method; content:"debug"; nocase; http_uri; content:"hash"; nocase; http_uri; metadata:cve CVE-2023-23958; classtype:attempted-recon; sid:9000001; rev:1;)

Elastic Detection

sequence by host.id, source.ip with maxspan=1m
  [network where event.type == "start" and destination.port == 443 and
   network.protocol == "http"]
  [http where http.request.method in ("GET", "POST") and
   (url.path contains "debug" or url.path contains "diagnostic") and
   lower(http.response.body) like "*hash*"]

Splunk SPL Query

index=web sourcetype="symantec:protection_engine"
| where status IN (400, 401, 403, 500, 502, 503)
| regex uri="(debug|diagnostic|status|error)"
| regex response_body="(?i)(hash=|md5=|sha1=|token=|credential)"
| table _time, src_ip, dest_ip, uri, status, response_body
| sort - _time

Wazuh OSSEC Rule

<group name="symantec,">
  <rule id="100421" level="8">
    <decoded_as>syslog</decoded_as>
    <match>Hash Leak|hash vulnerability</match>
    <regex>Symantec Protection Engine</regex>
    <description>Potential Symantec Protection Engine hash leak exploitation (CVE-2023-23958)</description>
    <group>attack,reconnaissance,information_disclosure</group>
    <mitre>
      <id>T1190</id>
      <id>T1005</id>
    </mitre>
  </rule>
</group>

Mitigation & Patch Guidance

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

1. Immediate Mitigations:

   • Restrict network access to Symantec Protection Engine interfaces to trusted internal networks only.
   • Implement network segmentation to prevent direct Internet exposure of SPE servers.
   • Enable logging and monitoring on all SPE instances to detect anomalous access patterns.

2. Patch/Upgrade Steps:

   • Upgrade to Symantec Protection Engine version 9.1.0 or later, per the CNA claim.
   • Verify the patch independently with Symantec's official advisory before production deployment.
   • Test the upgrade in a staging environment that mirrors production configurations.

3. Long-Term Hardening:

   • Subscribe to Symantec security advisories for proactive vulnerability notifications.
   • Conduct regular vulnerability scans of security infrastructure components.
   • Implement a patch management process with defined SLAs for security products.
   • Consider deploying SPE behind a load balancer or WAF that can filter suspicious requests.

References

1. NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2023-23958
2. CNA Advisory: Symantec (Broadcom) — Patch claim for version 9.1.0 release notes
3. CISA KEV Catalog: Not listed — no known exploitation in the wild
4. EPSS Score Reference: https://www.first.org/epss/ (EPSS 0.00515)
5. Nuclei/PoC Sources: No public PoC or template identified as of reporting date

Threat Actor Campaigns: No known threat actor campaigns have been associated with CVE-2023-23958. The absence of successful exploitation reports, combined with the low EPSS score, suggests this vulnerability has not yet attracted significant attacker interest.