Privacy and Security Risks in the eSIM Ecosystem [pdf]

Original Article ↗ Hacker News Discussion ↗

Physical SIM vs eSIM: Control, Reliability, and Fees

  • Many prefer physical SIMs for easy, offline swapping between devices (including dumbphones) and as a hard kill‑switch for connectivity.
  • eSIM is seen as adding dependencies: carrier backends, apps, QR codes, Wi‑Fi/Internet, and carrier approval for transfers.
  • Reports of fees and swap limits for eSIM in parts of Europe; others (e.g. Australia) say eSIM is free, self‑service, and reversible to physical SIM.
  • Some view eSIM as a step back toward device/IMEI‑locked models (CDMA‑style) and loss of user ownership over the subscription.

Travel eSIMs, Routing, and Latency

  • The paper’s main risks are tied to travel eSIM resellers/MVNOs: opaque provisioning, third‑party routing, profile lock‑in, and deletion failures.
  • Several travelers found their traffic unexpectedly routed via Hong Kong/China, affecting latency, geolocation, and access to services (e.g., ChatGPT).
  • Some say this is just home‑routed roaming via low‑cost networks; others are uncomfortable with routing through more surveilled jurisdictions.

Privacy, Metadata, and TLS/DNS

  • Debate over whether routing via China “matters” if TLS is used:
    • One side: content is encrypted, so risk is limited.
    • Other side: metadata (who talks to whom, when, SNI hostnames) is highly sensitive regardless of TLS.
  • Concerns about not being able to set DNS/DoH for cellular on some platforms, captive portal breakage with DoH, and pervasive third‑party tracking by carriers and “tech” companies.

Regional Policies and Censorship

  • China: domestic phones can only activate Chinese eSIMs; foreign eSIM activation within China is blocked. Some argue this is to preserve the Great Firewall and kill gray‑market imports; earlier claims that eSIMs “stop working when leaving China” were corrected.
  • Germany: claim that SIM‑less emergency calls were disabled due to abuse; others express shock and uncertainty about current behavior.

Security, Lock‑In, and Ecosystem Critique

  • eSIM enables new reseller ecosystems with low entry barriers, which can mean cheaper travel data but weaker regulation, privacy, and support.
  • Some carriers allegedly whitelist specific device models/IMEIs for eSIM, undermining the “just move the SIM” paradigm.
  • Multiple anecdotes of painful eSIM onboarding, app requirements, one‑time QR codes, and failure to re‑provision after device loss, contrasted with rare but real physical‑SIM issues.

Workarounds and Tools

  • Heavy use of WireGuard/VPNs to neutralize routing and DNS issues, with minimal reported battery overhead but possible UDP de‑prioritization.
  • Hardware like 9eSIM/sysmoEUICC is praised as a bridge: a physical card that can host multiple eSIM profiles and be moved between devices, though some providers reject such setups.

Assessment of the Paper/Title

  • Several readers say the real problem is the unregulated international reseller market and MVNO practices, not eSIM technology itself, and find the title somewhat misleading without that qualifier.