AWS - Lambda Post Exploitation

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Lambda

Para más información, consulta:

AWS - Lambda Enum

Exfiltrar credenciales de Lambda

Lambda usa variables de entorno para inyectar credenciales en tiempo de ejecución. Si puedes acceder a ellas (leyendo /proc/self/environ o usando la propia función vulnerable), puedes utilizarlas tú mismo. Se almacenan en los nombres de variable por defecto AWS_SESSION_TOKEN, AWS_SECRET_ACCESS_KEY y AWS_ACCESS_KEY_ID.

Por defecto, estas tendrán acceso para escribir en un cloudwatch log group (cuyo nombre se almacena en AWS_LAMBDA_LOG_GROUP_NAME), así como para crear log groups arbitrarios; sin embargo, las funciones de Lambda frecuentemente tienen más permisos asignados según su uso previsto.

lambda:Delete*

Un atacante al que se le conceda lambda:Delete* puede eliminar funciones de Lambda, versiones/alias, layers, event source mappings y otras configuraciones asociadas.

aws lambda delete-function \
--function-name <LAMBDA_NAME>

Steal Others Lambda URL Requests

Si un atacante de alguna manera logra obtener RCE dentro de una Lambda, podrá robar las solicitudes HTTP de otros usuarios dirigidas a la Lambda. Si las solicitudes contienen información sensible (cookies, credenciales…) podrá exfiltrarlas.

AWS - Lambda Steal Requests

Steal Others Lambda URL Requests & Extensions Requests

Abusando de Lambda Layers también es posible abusar de extensions y persistir en la Lambda, además de robar y modificar solicitudes.

AWS - Abusing Lambda Extensions

AWS Lambda – VPC Egress Bypass

Force a Lambda function out of a restricted VPC by updating its configuration with an empty VpcConfig (SubnetIds=[], SecurityGroupIds=[]). The function will then run in the Lambda-managed networking plane, regaining outbound internet access and bypassing egress controls enforced by private VPC subnets without NAT.

AWS - Lambda VPC Egress Bypass

AWS Lambda – Runtime Pinning/Rollback Abuse

Abuse lambda:PutRuntimeManagementConfig to pin a function to a specific runtime version (Manual) or freeze updates (FunctionUpdate). This preserves compatibility with malicious layers/wrappers and can keep the function on an outdated, vulnerable runtime to aid exploitation and long-term persistence.

AWS - Lambda Runtime Pinning Abuse

AWS Lambda – Log Siphon via LoggingConfig.LogGroup Redirection

Abuse lambda:UpdateFunctionConfiguration advanced logging controls to redirect a function’s logs to an attacker-chosen CloudWatch Logs log group. This works without changing code or the execution role (most Lambda roles already include logs:CreateLogGroup/CreateLogStream/PutLogEvents via AWSLambdaBasicExecutionRole). If the function prints secrets/request bodies or crashes with stack traces, you can collect them from the new log group.

AWS - Lambda LoggingConfig Redirection

AWS - Lambda Function URL Public Exposure

Turn a private Lambda Function URL into a public unauthenticated endpoint by switching the Function URL AuthType to NONE and attaching a resource-based policy that grants lambda:InvokeFunctionUrl to everyone. This enables anonymous invocation of internal functions and can expose sensitive backend operations.

AWS - Lambda Function URL Public Exposure

AWS Lambda – Event Source Mapping Target Hijack

Abuse UpdateEventSourceMapping to change the target Lambda function of an existing Event Source Mapping (ESM) so that records from DynamoDB Streams, Kinesis, or SQS are delivered to an attacker-controlled function. This silently diverts live data without touching producers or the original function code.

AWS - Lambda Event Source Mapping Hijack

AWS Lambda – EFS Mount Injection data exfiltration

Abuse lambda:UpdateFunctionConfiguration to attach an existing EFS Access Point to a Lambda, then deploy trivial code that lists/reads files from the mounted path to exfiltrate shared secrets/config that the function previously couldn’t access.

AWS - Lambda EFS Mount Injection

Tip

Aprende y practica AWS Hacking:HackTricks Training AWS Red Team Expert (ARTE)
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Aprende y practica Az Hacking: HackTricks Training Azure Red Team Expert (AzRTE)

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