CWE-1284: Improper Validation of Specified Quantity in Input
The product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties.
How it's found
Improper Validation of Specified Quantity in Input is typically found by tracing untrusted input from where it enters the system to the point where it is used without the check or neutralization this weakness describes, combining manual code review with dynamic testing.
Specified quantities include size, length, frequency, price, rate, number of operations, time, and others. Code may rely on specified quantities to allocate resources, perform calculations, control iteration, etc.
Vulnerable vs. safe
owner: context.repo.owner,repo: context.repo.repo,run_id: ${{ github.event.workflow_run.id }},
return artifact.name == "pr"
owner: context.repo.owner,repo: context.repo.repo,artifact_id: matchPrArtifact.id,archive_format: 'zip',var artifacts = await github.actions.listWorkflowRunArtifacts({});var matchPrArtifact = artifacts.data.artifacts.filter((artifact) => {})[0];var downloadPr = await github.actions.downloadArtifact({});var fs = require('fs');fs.writeFileSync('${{github.workspace}}/pr.zip', Buffer.from(downloadPr.data));script: |
unzip pr.zipecho "pr_number=$(cat NR)" >> $GITHUB_ENV- name: 'Download artifact'uses: actions/github-scriptwith:- run: |runs-on: ubuntu-lateststeps:deploy:name: Deploy Previewjobs:The code could be modified to validate that the NR
file only contains a numeric value, or the code could
retrieve the PR number from a more trusted source.Consequences
- Varies by Context, DoS: Resource Consumption (CPU), Modify Memory, Read Memory: When the quantity is not properly validated, then attackers can specify malicious quantities to cause excessive resource allocation, trigger unexpected failures, enable buffer overflows, etc.
Mitigations
- Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
Where this fits in a TurboPentest engagement
This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.
Frequently asked questions
What is CWE-1284?
The product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties.
How do you find Improper Validation of Specified Quantity in Input?
Improper Validation of Specified Quantity in Input is typically found by tracing untrusted input from where it enters the system to the point where it is used without the check or neutralization this weakness describes, combining manual code review with dynamic testing.
What is the impact of CWE-1284?
Varies by Context, DoS: Resource Consumption (CPU), Modify Memory, Read Memory: When the quantity is not properly validated, then attackers can specify malicious quantities to cause excessive resource allocation, trigger unexpected failures, enable buffer overflows, etc.
Does TurboPentest test for Improper Validation of Specified Quantity in Input?
This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.
Related CWEs
Written and reviewed by
Michel Chamberland - Founder & CEO, IntegSec
CISSP, OSCP, OSCE, CEH, GIAC, CCSK · 20+ years in offensive security
Michel has spent 20+ years on offensive security teams including IBM X-Force Red and Trustwave SpiderLabs, leading penetration tests, red team engagements, and breach response for Fortune 500 customers. He is the founder of IntegSec and the architect of TurboPentest.
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