Choosing the Unified SASE Provider: The Execution Isolation Factor

Shared Processes for Packet-level Security Technologies

Networking and security technologies at the packet level, such as stateful inspection firewalls, IPSEC, and load balancing, impose lower computational demands in terms of the number of CPU cycles required for each packet. Furthermore, the processing per packet is highly consistent, simplifying performance prediction.

In today’s landscape, security functions (e.g., FWaaS) are delivered as services by service providers who deploy these functions in the Cloud/Points of Presence (PoPs). To cater to multiple tenants, the underlying security technology implementations leverage a Virtual Routing and Forwarding (VRF) tenancy model. Under this model, traffic from multiple tenants traverses the same security device or container/process, effectively addressing challenges related to overlapping IP addresses among tenants. Tenant traffic is identified either through tunnel interfaces or other mechanisms, and specific configurations tailored to each tenant, such as tenant-specific security policies, are then applied accordingly.

To mitigate any potential “noisy neighbor” issues, packet rate limiting is applied at the ingress on a per-tenant basis. This strategy guarantees that the security performance of each individual tenant remains unaffected by the activities of other potentially problematic tenants. Given the consistent per-packet processing, rate limiting proves effective in ensuring equitable processing treatment for all tenants.

Another significant concern for organizations is the potential leakage of sensitive data resulting from the exploitation of vulnerabilities within shared processes or containers by malicious packets from other tenants. One argument often presented by security service providers is that the processing on a per-packet basis is straightforward, reducing the likelihood of vulnerabilities and corresponding exploitation. It is indeed true that packet-level security technologies are simpler, and this argument has some validity.

Both challenges mentioned earlier, namely the “noisy neighbor” problem and “shared resource vulnerabilities,” may not pose significant issues for packet-level security technologies that utilize shared processes. However, we believe that these challenges can be more pronounced and substantial for SASE (Secure Access Service Edge) or SSE (Secure Service Edge) security technologies.

Distinguishing SASE/SSE Security from Packet-Level Security Technologies and Challenges

SASE/SSE (Secure Access Service Edge/Secure Service Edge) security technologies transcend traditional packet-level security, offering a comprehensive suite of features:

  • Comprehensive Security Functions: SASE/SSE encompasses a wide array of security functions, including IDPS (Intrusion Detection and Prevention), DNS Security, SWG (Secure Web Gateway), ZTNA (Zero Trust Network Access), CASB (Cloud Access Security Broker) with IP/URL/Domain/File reputation firewall, access control with deep traffic-level attributes such as URI, request headers, response headers, Anti-Malware, and DLP (Data Leak Prevention). Zero Trust Networking (ZTN) in SASE/SSE is fundamental, ensuring access only upon user authentication and authorization, with granular control over application resources while considering identity and device context.
  • Deep Content Inspection: The core of SASE/SSE security lies in deep content inspection. Utilizing proxies that manage client connections, initiate server connections, decrypt streams, extract relevant data from traffic, perform security functions, and prevent the transmission of malicious content.

Now, let’s delve into the execution differences between SASE/SSE and packet-level security technologies:

  • Shift from Per-Packet to Session-Based Processing: In the context of SASE/SSE, security execution no longer operates at the per-packet level but rather at the level of traffic session streams. Unlike per-packet technologies, there is variability in the number of compute cycles used in SASE/SSE security processing across tenants, for the following reasons:
    • Security functions applied to the traffic stream can vary among tenants.
    • Even when similar security functions are applied, the nature of the data being exchanged can necessitate more intensive processing. For example, consider scenarios involving Anti-Malware and DLP, which require extracting text from various file types, decompressing transferred files, untarring file collections, and more. Some tenants may transfer compressed files, resulting in extensive processing, impacting throughput and latency for other tenants. Noise generated by a particular tenant, whether due to infection or high business traffic during a significant event, can affect other tenants’ traffic performance.
  • Complex Security Processing: SASE/SSE security processing is inherently intricate, often incorporating various libraries, including third-party and open-source components. These encompass functions such as OIDC (OpenID Connect) clients, Kerberos clients, SAMLv2 clients for authentication, complex policy engines for enforcement, SDKs from threat intelligence providers, data extraction , JSON/XML decoding, base64 decoding, data decompression engines, and text extraction via open-source projects like Tika, among others for data level security such as Anti-Malware and DLP. This complexity increases the attack surface for potential exploitation. Although SASE/SSE providers prioritize swiftly addressing vulnerabilities, a time gap may exist between exploitation and resolution. When shared processes are employed for multiple tenants, attackers can potentially exploit vulnerabilities and access sensitive information from not only the intended tenant but also all tenants’ data sharing that execution context.
  • Bring your own Security Function: While SASE/SSE services offer comprehensive security features out of the box, they also provide organizations with the flexibility to introduce their custom security functions using Lua modules or WebAssembly (WASM) modules. However, in such cases, shared processes pose significant challenges, as they can potentially lead to data exfiltration from other tenants if not managed carefully. Addressing this concern becomes more complex when shared processes are employed, and there may always be potential ways to circumvent these controls.

In summary, SASE/SSE security offers a comprehensive security framework beyond packet-level security, but it introduces complexities and challenges related to variable compute usage, intricate processing, and shared resources. Maintaining robust security in such environments is critical to safeguard against performance challenges AND data breaches & privacy violations.

Seek SASE/SSE Solutions that Offer Execution Isolation

Organizations undoubtedly value the rationale behind SASE/SSE providers employing shared processes for multiple tenants. This approach efficiently utilizes compute resources among tenants, contributing to sustainability and cost-effectiveness. Service providers can, in turn, pass on these cost savings to their customers.

However, certain industry segments are reluctant to accept the security risks associated with multi-tenancy architecture and shared processes. Some organizations may anticipate future needs for a more risk-averse approach. In such cases, organizations should seek SASE/SSE services that offer flexibility, providing options for both shared processes and dedicated processes/containers.

Dedicated execution contexts with dedicated processes/containers for traffic processing, can effectively address the challenges outlined in the previous section:

  • Performance Isolation: Achieving deterministic performance becomes feasible without concerns about disruptive “noisy tenants.” With a dedicated execution context, it is relatively straightforward to allocate dedicated compute resources to individual tenants. One can also configure resource caps from noisy neighbors using up all resources in the compute nodes.
  • Security Isolation: A dedicated execution context ensures that any malicious intent or insider threats attempting to exploit SASE/SSE services of one tenant will not lead to data leakage for tenants that opt for dedicated execution contexts.
  • Worry free ‘Bring your own security function’: A dedicated execution context unquestionably ensures that Lua scripts/WASM modules are exclusively executed within dedicated processes. Consequently, any processing or data exfiltration challenges are confined to the tenant bringing their custom security functions, providing peace of mind for other tenants in this regard, if service providers enable this feature only for dedicated processes.

Anticipating Future Needs: The Importance of Confidential Computing

As we look ahead, some organizations are becoming increasingly aware of the growing importance of confidential computing. This awareness is particularly relevant in the context of TLS inspection and the management of numerous sensitive data, including secrets and passwords, within SASE/SSE services. A recurring concern revolves around the possibility that personnel with access to the server infrastructure, including service provider staff, might gain unauthorized access to the memory of processes and containers. Additionally, even attackers who manage to exploit server operating systems may potentially breach the memory of these containers and processes. This concern becomes more pronounced in situations where services are available in multiple Points of Presence (POPs) across different countries with varying levels of legal definitions and implementations.

Modern processors, such as those equipped with Intel Trust Domain Extensions (TDx), offer advanced features for trusted execution. These technologies play a crucial role in ensuring that even infrastructure administrators or attackers with elevated privileges cannot decipher the memory content, as it remains securely encrypted by TDx hardware.

SASE/SSE providers that offer dedicated execution contexts are better positioned to provide this essential confidentiality feature compared to others. Therefore, organizations are strongly advised to consider providers that offer the flexibility of both shared processes and dedicated execution contexts. This flexibility will help future-proof their risk mitigation strategies and ensure the highest level of data security in evolving landscapes.

  • CTO Insights blog

    The Aryaka CTO Insights blog series provides thought leadership for network, security, and SASE topics. For Aryaka product specifications refer to Aryaka Datasheets.

About the author

Srini Addepalli
Srini Addepalli is a security and Edge computing expert with 25+ years of experience. Srini has multiple patents in networking and security technologies. He holds a BE (Hons) degree in Electrical and Electronics Engineering from BITS, Pilani in India.