Linux Curl Upload File
The following analytic identifies curl being utilized with the -F or –form, –upload-file, -T, -d, –data, –data-raw, -I and –head switches to upload AWS credentials or config to a remote destination. This enables uploading of binary files and so forth. To force the 'content' part to be a file, prefix the file name with an @ sign. To just get the content part from a file, prefix the file name with the symbol <. The difference between @ and < is then that @ makes a file get attached in the post as a file upload, while the < makes a text field and just get the contents for that text field from a file. This technique was utlized by the TeamTNT group to exfiltrate AWS credentials.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2022-07-29
- Author: Michael Haag, Splunk
- ID: c1de2d9a-0c02-4bb4-a49a-510c6e9cf2bf
Kill Chain Phase
- Command and Control
- CIS 10
1 2 3 4 5 6 | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name=curl Processes.process IN ("*-F *", "*--form *","*--upload-file *","*-T *","*-d *","*--data *","*--data-raw *", "*-I *", "*--head *") AND Processes.process IN ("*.aws/credentials*". "*.aws/config*") by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `linux_curl_upload_file_filter`
The SPL above uses the following Macros:
linux_curl_upload_file_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
How To Implement
To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the
Endpoint datamodel in the
Processes node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.
Known False Positives
Filtering may be required. In addition to AWS credentials, add other important files and monitor. The inverse would be to look for all -F behavior and tune from there.
Associated Analytic Story
|64.0||80||80||An instance of $process_name$ was identified on endpoint $dest$ by user $user$ attempting to upload important files to a remote destination.|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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replay.py tool or the UI.
Alternatively you can replay a dataset into a Splunk Attack Range
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