AVML (Acquire Volatile Memory for Linux)

Summary

A portable volatile memory acquisition tool for Linux.

AVML is an X86_64 userland volatile memory acquisition tool written in Rust, intended to be deployed as a static binary. AVML can be used to acquire memory without knowing the target OS distribution or kernel a priori. No on-target compilation or fingerprinting is needed.

Build Status

Features

• Save recorded images to external locations via Azure Blob Store or HTTP PUT
• Automatic Retry (in case of network connection issues) with exponential backoff for uploading to Azure Blob Store
• Optional page level compression using Snappy.
• Uses LiME output format (when not using compression).

Memory Sources

• /dev/crash
• /proc/kcore
• /dev/mem

If the memory source is not specified on the commandline, AVML will iterate over the memory sources to find a functional source.

Tested Distributions

• Ubuntu: 12.04, 14.04, 16.04, 18.04, 18.10, 19.04, 19.10
• Centos: 6.5, 6.6, 6.7, 6.8, 6.9, 6.10, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6
• RHEL: 6.7, 6.8, 6.9, 7.0, 7.2, 7.3, 7.4, 7.5, 8
• Debian: 8, 9
• Oracle Linux: 6.8, 6.9, 7.3, 7.4, 7.5, 7.6

Getting Started

To grab a compressed memory image:

avml --compress output.lime

To upload to Azure Blob Store:

# On a host with az cli credentials
EXPIRY=$(date -d '1 day' '+%Y-%m-%dT%H:%MZ') 
SAS=$(az storage blob generate-sas --account-name ACCOUNT --container CONTAINER -n test.lime --full-uri --permissions c --output tsv --expiry ${EXPIRY})

# On the target host
avml --sas_url $(SAS) --delete output.lime

To execute on a VM in Azure using VM Extensions:

# On a host with az cli credentials, build a config.json containing the following info:
{
    "commandToExecute": "./avml --compress --sas_url <SAS_URL_HERE> --delete",
    "fileUris": [
        "https://FULL.URL.TO.AVML.example.com/avml"
    ]
}
# Use az cli to execute the customScript extension with the aformentioned config.json
az vm extension set -g RESOURCE_GROUP --vm-name VM_NAME --publisher Microsoft.Azure.Extensions -n customScript --settings config.json

To upload to AWS S3:

# Generate presigned URL on secure host

# On the target host
avml --put ${URL} --delete output.lime

Usage

``` avml [FLAGS] [OPTIONS]

FLAGS: --compress compress pages via snappy --delete delete upon successful upload -h, --help Prints help information -V, --version Prints version information

OPTIONS: --sasblocksize specify maximum block size in MiB --sas_url Upload via Azure Blob Store upon acquisition --source specify input source [possible values: /proc/kcore, /dev/crash, /dev/mem] --url Upload via HTTP PUT upon acquisition.

ARGS: name of the file to write to on local system ```

Building on Ubuntu

# Install MUSL
sudo apt-get install musl-dev musl-tools musl

# Install Rust via rustup
curl https://sh.rustup.rs -sSf | sh -s -- -y

# Add the MUSL target for Rust
rustup target add x86_64-unknown-linux-musl

# Build
cargo build --release --target x86_64-unknown-linux-musl

# Build without upload functionality
cargo build --release --target x86_64-unknown-linux-musl --no-default-features

Testing on Azure

The testing scripts will create, use, and cleanup a number of resource groups, virtual machines, and a storage account.

1. Install az cli
2. Login to your Azure subscription using: az login
3. Build avml (see above)
4. ./test/run.sh

Contributing

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.microsoft.com.

When you submit a pull request, a CLA-bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., label, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repositories using our CLA.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.

Reporting Security Issues

Security issues and bugs should be reported privately, via email, to the Microsoft Security Response Center (MSRC) at secure@microsoft.com. You should receive a response within 24 hours. If for some reason you do not, please follow up via email to ensure we received your original message. Further information, including the MSRC PGP key, can be found in the Security TechCenter.