Topic starter
18/08/2026 2:16 pm
TL;DR: Encoded text files can hide customer records, payment data, and other sensitive content inside files that scanners often mark clean, according to Sentra. The real risk is inventory error: once disguised data is classified as harmless text, downstream security, compliance, and breach-scoping decisions inherit that mistake.
Editorial analysis by NHI Mgmt Group, based on content published by Sentra: “The Oldest Trick in the Book: Sensitive Data Hiding in "Plain Text"”.
By the numbers:
- Encoded files disguised as plain text appeared in 40% of the environments scanned during development.
- Sentra found 23 encoded archives in one financial services data lake.
Key questions
Q: What breaks when encoded files are treated as plain text?
A: The inventory breaks first, because the scanner records the file as harmless even when it contains sensitive material after decoding.
Q: Why do encoded text files create compliance and breach-scoping risk?
A: Because compliance and incident response both depend on knowing what data was actually stored, moved, or exposed.
Q: What are the signs that data classification is missing concealed payloads?
A: Look for repeated clean scans on files that later decode into archives, database exports, or regulated records.
Practitioner guidance
- Inspect decoded content, not only file labels Require your data security tooling to open and classify nested encoded content, including base64, hex, gzip, and multi-layer wrappers, before it marks a file clean.
- Treat concealment as a separate finding Record hidden payloads as concealed data events so analysts can distinguish ordinary text from disguised content that may indicate exfiltration, poor handling, or evasion.
- Re-scope stored files already marked safe Re-evaluate cloud shares, repositories, and backups for encoded archives or exports that may have been scanned as text and left unclassified for years.
Bottom line: Encoded text files can hide regulated data inside files that scanners may classify as safe, creating a blind spot in data security inventory.
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18/08/2026 3:09 pm
Concealed payloads create inventory debt: once encoded content is labelled clean, the error propagates into every downstream decision that depends on asset truth. Security teams do not just miss a file, they inherit a false record of what data exists and where it lives. That makes the inventory itself a governance control, not a reporting convenience. Practitioners should treat hidden payloads as a structural data governance failure.
A few things that frame the scale:
- 43% of security professionals are concerned about AI systems learning and reproducing sensitive information patterns from codebases, according to the State of Secrets in AppSec.
A question worth separating out:
Q: How should teams respond when concealed data is discovered in storage?
A: Treat the discovery as a data governance event, not just a file cleanup task. Decode the content, identify the real data class, check where copies exist, and update the inventory so access, retention, and incident-response decisions reflect the actual exposure. If the concealment looks intentional, escalate for investigation rather than routine remediation.
👉 Read our full editorial: Encoded text files create a data security blind spot