A Growing Trend in Misusing Traffic Light Protocol Labels as Internal Classification Schemes Has Security Experts Concerned
As cybersecurity professionals, we’ve all heard of the Traffic Light Protocol (TLP), a widely recognized standard for communicating whether sensitive information can be shared further and with whom. But what’s become increasingly clear is that many organizations are attempting to use TLP labels as a replacement for their internal information classification schemes – and it’s not working out well.
On the surface, this might seem like a reasonable approach. After all, TLP defines simple labels (TLP:GREEN, TLP:AMBER, etc.) that indicate whether information can be shared within an organization or with external parties. And most organizational classification schemes also consist of only a few levels, making it easy to see why organizations would consider using TLP as a one-size-fits-all solution.
However, this approach has several critical flaws. First and foremost, the official TLP 2.0 standard explicitly states that “TLP is not a formal classification scheme” and was never designed to define information handling or encryption rules. Its purpose is to specify with whom information may be shared, not how it should be protected. This means that using TLP labels as a replacement for internal classification schemes ignores the nuances of information protection requirements, such as encryption, storage, access control, and retention.
For example, an organization might allow documents labeled “Sensitive” to be sent to customers in encrypted emails or on encrypted USB drives – but this requirement cannot be inferred from a TLP label alone. To express these requirements using TLP would require organizations to add their own information handling rules to the labels, essentially creating a custom classification scheme.
Moreover, the sharing restrictions defined by TLP don’t necessarily correspond to what one might expect from similarly named internal classification levels. For instance, an organization that uses TLP:GREEN to mark documents intended for internal use may inadvertently allow external security partners to distribute them further, even if this wasn’t the intention of the original organization.
A similar problem arises with TLP:AMBER, which permits sharing not only within an organization but also with clients on a need-to-know basis. This can lead to confusion and unintended information leaks when organizations use these labels as internal classification levels without understanding their intended usage.
The trend of using TLP labels as internal classification schemes is particularly problematic because it often results in the misuse of sensitive information. When organizations assign TLP labels based solely on document sensitivity rather than who should be able to receive it, they may inadvertently create labels that are either too restrictive or too permissive for legitimate sharing needs.
While organizations can certainly define additional restrictions or their own interpretations of these labels, doing so effectively means creating a custom classification scheme that only looks like TLP. This can lead to misunderstandings whenever information is exchanged with anyone who follows the actual standard.
So what’s the takeaway from this trend? While TLP has its place in cybersecurity – particularly for sharing threat intelligence and security-related information – it should not be used as a replacement for internal classification schemes. Organizations must recognize that TLP was never intended to serve this purpose, and instead use it only where it makes sense: when communicating with external parties about sensitive information. By doing so, we can avoid the confusion and potential security risks associated with misusing these labels and ensure that our internal classification schemes are robust, effective, and aligned with industry standards.
Source: SANS ISC — 2026-10-10