QNAP TS-251

Security Evaluation

1. Device Security

Criterion	Value	Proof	Comment
Known hardware tampering	Rare	🔗 Proof	Qualitative Rare: documented local USB recovery can rewrite internal DOM. Physical-access resistance judgment, not measured tampering incidence.
Known vulnerabilities	Rare	[1] 🔗 Proof	Qualitative Rare for documented 2018 VPNFilter issue: QNAP affected-build advisory plus Talos exact-model list. No measured frequency or claim all updated units remain vulnerable.
Prior attacks	Rare	🔗 Proof	Talos 2018 names this exact model as VPNFilter Known Affected. Rare is qualitative for one campaign; infected build and per-model counts unknown.
Updatability	Very common	🔗 Proof	As-of2026-10-20 exact-model API lists 8 2026 releases; latest 5.2.11.3652 Build 20261014 published 2026-10-20. Qualitative cadence, not historical4.2.1 defaults.
Category Score	Score: 2 / 3

2. System Security

Criterion	Value	Proof	Comment
Authentication with other systems	Partial	🔗 Proof	QTS4.2.1: optional iSCSI CHAP and Mutual CHAP; partial device-wide authentication, not universally enforced peer authentication.
Communications	No encryption	🔗 Proof	QTS4.2.1 HTTP management: p28 http://NAS IP:8080. Optional HTTPS and force-HTTPS exist (p28,p48); not all traffic plaintext and not a device test.
Storage	No encryption	[2] 🔗 Proof	No encryption only for documented internal DOM configuration filesystem: direct ext2 mount and factory-image inspection. Not all partitions/secrets; not a live QTS4.2.1 dump.
Category Score	Score: 3 / 3

3. User Authentication

Criterion	Value	Proof	Comment
Account management	Full	[3] 🔗 Proof	QTS4.2.1: ordinary users/passwords/groups/folder rights; legacy Users UI has Delete. Built-in admin undeletable; no deletion test performed.
Authentication	Basic	🔗 Proof	QTS4.2.1 username/password with configurable physical reset restoring admin password. Basic for recovery-capable scope; no remote hardcoded-backdoor claim.
Brute-force protection	Exist	🔗 Proof	QTS4.2.1 Network Access Protection can block IPs after failed logins for a period/indefinitely. Configurable, not asserted enabled by default.
Event logging	Access event logged	🔗 Proof	QTS4.2.1 configurable connection/file-action logging; AFP/SSH login/logout only. Start Logging required; not every protocol or factory-enabled logging.
Passwords	Default/Common/Easy to guess	🔗 Proof	Historical QTS4.2.1 manual p28: admin/admin; physical reset also restores admin. Not a current QTS5.2 password claim.
Category Score	Score: 2 / 3

Technical Specifications

Property	Details
Operating System & App	Historical QTS 4.2.1 behavior; update cadence separately as-of 2026-10-20 (Companion App: )
Hardware (CPU / GPU)	CPU: • GPU:
Memory & Storage	Memory: • Storage:
Power, Battery & Charging	Battery: • Power: • Charging:
Display & Camera	Display: • Camera:
Sound & Connectivity	Sound: • Connectivity:
Physical (Dimensions & Mass)	Dimensions: • Mass:

Historical QTS4.2.1 documentary assessment, HTTP management path; capabilities such as logging/IP blocking/CHAP are configurable, not claimed defaults. VPNFilter is separately dated2018; infected builds unknown. Update cadence alone is as-of2026-10-20. Not current-password claims, a device test, or one observed deployment. Release date is public announcement, not proven first shipment. Announcement source: https://www.qnap.com/en/news/2014/qnap-releases-cutting-edge-home-nas-with-expansion-solution-ts-x51-series-featuring-dual-core-intel-celeron-2-41ghz-processor. Storage assesses unencrypted internal-DOM config filesystem, not HDD AES or every secret; factory2014 recovery image is not a running QTS4.2.1 dump. Parent independently checked exact source byte-range (206) and ext2 with read-only debugfs; filesystem contains lost+found, no credentials recovered. Manual explicitly includes original TS-251; no TS-251+ substitution. Physical category considers USB reimaging internal DOM, not measured malicious incidents. Built-in admin cannot be deleted; account lifecycle score concerns ordinary users.