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CVE Record

CVE-2005-3374: Multiple interpretation error in F-Prot 3.16c allows remote attackers to bypass virus scanning via a file s...

Multiple interpretation error in F-Prot 3.16c allows remote attackers to bypass virus scanning via a file such as BAT, HTML, and EML with an "MZ" magic byte sequence which is normally associated with EXE, which causes the file to be treated as a safe type that could still be executed as a dangerous file type by applications on the end system, as demonstrated by a "triple headed" program that contains EXE, EML, and HTML content, aka the "magic byte bug."

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's Takeunknown

Analyst readout for executives and security teams

Plain-English summary

This CVE describes a way to make F-Prot 3.16c misread certain files, so virus scanning may treat a risky attachment as safe. The issue matters most where this old antivirus engine still protects email, web downloads, or file gateways.

Executive priority

Treat this as a legacy-control risk. It is not KEV-listed and lacks modern severity data, but affected environments may have a blind spot in malware filtering that should be removed during antivirus modernization.

Technical view

F-Prot 3.16c had a multiple-interpretation parsing issue involving files such as BAT, HTML, and EML containing an MZ magic byte sequence. Sources describe scanner classification differing from how endpoint applications may execute or render the same file, enabling antivirus detection evasion.

Likely exposure

Exposure appears limited to environments still using F-Prot 3.16c or dependent products embedding that engine. The bundle does not identify broader affected versions, CPEs, supported platforms, or current vendor patch status.

Exploitation context

The sources describe a demonstrated detection-evasion technique, including a triple-format file concept. CISA KEV status is false, and the provided bundle does not cite active exploitation in the wild.

Researcher notes

Evidence is sparse and old. The core issue is parser disagreement: F-Prot classification can differ from downstream application behavior. Avoid assuming affected products beyond F-Prot 3.16c unless vendor documentation confirms engine reuse.

Mitigation direction

  • Inventory any F-Prot 3.16c deployments or embedded scanning integrations.
  • Check vendor or successor-maintainer guidance for fixed versions or replacement paths.
  • Do not rely on this legacy scanner as the only attachment control.
  • Block or quarantine ambiguous executable-capable attachment types at mail and web gateways.
  • Retire unsupported antivirus engines from production scanning paths.

Validation and detection

  • Confirm whether F-Prot 3.16c exists on endpoints, mail gateways, or file-scanning services.
  • Review antivirus gateway policies for executable, EML, HTML, BAT, and mixed-content attachments.
  • Check whether another supported engine scans files after F-Prot classification.
  • Review historical mail and web quarantine logs for ambiguous attachment handling.
  • Document any compensating controls if immediate replacement is not possible.
Prepared
Confidence
medium
Sources
7

Public sources used

Based on public source material and reviewed before publication.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2005-3374 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
6Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.