Cleartext Transmission of Sensitive Information

The product transmits sensitive or security-critical data in cleartext in a communication channel that can be sniffed by unauthorized actors.


Many communication channels can be "sniffed" (monitored) by adversaries during data transmission. For example, in networking, packets can traverse many intermediary nodes from the source to the destination, whether across the internet, an internal network, the cloud, etc. Some actors might have privileged access to a network interface or any link along the channel, such as a router, but they might not be authorized to collect the underlying data. As a result, network traffic could be sniffed by adversaries, spilling security-critical data.

Applicable communication channels are not limited to software products. Applicable channels include hardware-specific technologies such as internal hardware networks and external debug channels, supporting remote JTAG debugging. When mitigations are not applied to combat adversaries within the product's threat model, this weakness significantly lowers the difficulty of exploitation by such adversaries.

When full communications are recorded or logged, such as with a packet dump, an adversary could attempt to obtain the dump long after the transmission has occurred and try to "sniff" the cleartext from the recorded communications in the dump itself. Even if the information is encoded in a way that is not human-readable, certain techniques could determine which encoding is being used, then decode the information.


The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

The following code attempts to establish a connection to a site to communicate sensitive information.

try {
  URL u = new URL("");
  HttpURLConnection hu = (HttpURLConnection) u.openConnection();
  OutputStream os = hu.getOutputStream();
catch (IOException e) {


Though a connection is successfully made, the connection is unencrypted and it is possible that all sensitive data sent to or received from the server will be read by unintended actors.

Example Two

In 2022, the OT:ICEFALL study examined products by 10 different Operational Technology (OT) vendors. The researchers reported 56 vulnerabilities and said that the products were "insecure by design" [REF-1283]. If exploited, these vulnerabilities often allowed adversaries to change how the products operated, ranging from denial of service to changing the code that the products executed. Since these products were often used in industries such as power, electrical, water, and others, there could even be safety implications.

Multiple vendors used cleartext transmission of sensitive information in their OT products.

Example Three

A TAP accessible register is read/written by a JTAG based tool, for internal use by authorized users. However, an adversary can connect a probing device and collect the values from the unencrypted channel connecting the JTAG interface to the authorized user, if no additional protections are employed.

Example Four

The following Azure CLI command lists the properties of a particular storage account:

az storage account show -g {ResourceGroupName} -n {StorageAccountName}

The JSON result might be:


  "name": "{StorageAccountName}",
  "enableHttpsTrafficOnly": false,
  "type": "Microsoft.Storage/storageAccounts"


The enableHttpsTrafficOnly value is set to false, because the default setting for Secure transfer is set to Disabled. This allows cloud storage resources to successfully connect and transfer data without the use of encryption (e.g., HTTP, SMB 2.1, SMB 3.0, etc.).

Azure's storage accounts can be configured to only accept requests from secure connections made over HTTPS. The secure transfer setting can be enabled using Azure's Portal (GUI) or programmatically by setting the enableHttpsTrafficOnly property to True on the storage account, such as:

az storage account update -g {ResourceGroupName} -n {StorageAccountName} --https-only true

The change can be confirmed from the result by verifying that the enableHttpsTrafficOnly value is true:


  "name": "{StorageAccountName}",
  "enableHttpsTrafficOnly": true,
  "type": "Microsoft.Storage/storageAccounts"


Note: to enable secure transfer using Azure's Portal instead of the command line:

Open the Create storage account pane in the Azure portal.

In the Advanced page, select the Enable secure transfer checkbox.

See Also

Comprehensive Categorization: Encryption

Weaknesses in this category are related to encryption.

ICS Communications: Frail Security in Protocols

Weaknesses in this category are related to the "Frail Security in Protocols" category from the SEI ETF "Categories of Security Vulnerabilities in ICS" as published in ...

OWASP Top Ten 2021 Category A02:2021 - Cryptographic Failures

Weaknesses in this category are related to the A02 category "Cryptographic Failures" in the OWASP Top Ten 2021.

Comprehensive CWE Dictionary

This view (slice) covers all the elements in CWE.

Weaknesses Addressed by ISA/IEC 62443 Requirements

This view (slice) covers weaknesses that are addressed by following requirements in the ISA/IEC 62443 series of standards for industrial automation and control systems...

Entries with Maintenance Notes

CWE entries in this view have maintenance notes. Maintenance notes are an indicator that an entry might change significantly in future versions. This view was created...

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