Query-based black-box attacks

This repository contains code to reproduce results from the paper:

Exploring the Space of Black-box Attacks on Deep Neural Networks
Arjun Nitin Bhagoji, Warren He, Bo Li and Dawn Song
ArXiv report: https://arxiv.org/abs/1712.09491

REQUIREMENTS

The code was tested with Python 2.7.12, Tensorflow 1.3.0 and Keras 1.2.2.

EXPERIMENTS

TRAINING MNIST MODELS

STANDARD TRAINING

To train Models A through D on the MNIST dataset, create a models directory and run train.py as follows:

python train.py models/modelA --type=0 --num_epochs=6 
python train.py models/modelB --type=1 --num_epochs=6 
python train.py models/modelC --type=2 --num_epochs=6 
python train.py models/modelD --type=3 --num_epochs=6 

ADVERSARIAL TRAINING

To obtain variants of Models A through D which are trained using standard adversarial training, run train_adv.py as follows:

python train_adv.py models/modelA_adv --type=0 --num_epochs=12 
python train_adv.py models/modelB_adv --type=1 --num_epochs=12
python train_adv.py models/modelC_adv --type=2 --num_epochs=12
python train_adv.py models/modelD_adv --type=3 --num_epochs=12

Note that the number of epochs is increased from 6 to 12. The magnitude of the adversarial perturbation used for the training images can be controlled with the -eps flag. The default value used for MNIST is 0.3.

ENSEMBLE ADVERSARIAL TRAINING

The train_adv.py script can also be run to obtain variants of Models A through D trained using ensemble adversarial training. For example, to train a variant of Model A that uses adversarial samples generated from Models A, B and C, as well samples generated from the current state of the model (as in standard adversarial training), run:

python train_adv.py models/modelA_ens models/modelA models/modelC models/modelD --type=0 --num_epochs=12

ITERATIVE ADVERSARIAL TRAINING

Using the --iter flag with train_adv.py allows for the training of variants of Models A through D using iterative adversarial training. For example, a variant of Model A with iterative adversarial training can be trained as follows:

python train_adv.py models/modelA_adv --type=0 --iter=1 --num_epochs=64

Note that this form of training needs a much higher number of epochs for the training to converge. Iterative adversarial samples are generated using 40 steps of magnitude 0.01 each by default. This can be changed in the train_adv.py script. The maximum perturbation magnitude is still set to 0.3. To train using only the adversarial loss, set the --ben flag to 0.

PRETRAINED CIFAR-10 MODELS

CIFAR-10 models are trained using the same techniques. We have uploaded a set of pretrained weights.

ATTACKING MNIST MODELS

For all attacks except the Random Pertubations attack, setting --targeted_flag=1 enables a targeted attack to be carried out. By default, the target for each sample is chosen uniformly at random from the set of class labels except the true label of that sample. For attacks that generate adversarial examples (not the baseline attacks), two loss functions can be used: the standard cross-entropy loss (use --loss_type=xent) and a logit-based loss (use --loss_type=cw).

BASELINE ATTACKS

In order to carry out an untargeted Difference of Means attack (on Model A for example), run the baseline_attacks.py script as follows:

python baseline_attacks.py models/modelA

This will run the attack for a pre-specified list of perturbation values. For attacks constrained using the infinity-norm, the maximum perturbation value is 0.5 and for attacks constrained using the 2-norm, it is 9.0. To carry out an untargeted Random Perturbations attack, the --alpha parameter is set to 0.6 (infinity-norm constraint) or 9.1 (2-norm constraint).

TRANSFERABILITY-BASED ATTACKS

To carry out a transferability-based attack on a single model (say Model B) using FGS adversarial examples generated for another single model (say Model A), run the transfer_attack_w_ensemble.py script as follows:

python transfer_attack_w_ensemble.py fgs models/modelA --target_model=models/modelB

An ensemble-based transferability attack can also carried out. For example, if the ensemble of local models consists of Models A, C and D, and the model being attacked is Model B, run transfer_attack_w_ensemble.py as follows:

python transfer_attack_w_ensemble.py fgs models/modelA models/modelC models/modelC --target_model=models/modelB

The transfer_attack_w_ensemble.py script also supports a number of other attacks including Iterative FGS, FGS with an initial random step and the Carlini-Wagner attack, all of which can be carried out for either a single local model or an ensemble of models.

If the --target_model option is not specified, then just the white-box attack success rates will be reported. Note that if the perturbation magnitude is not specified using the --eps option, then a default set of perturbation values will be used.

QUERY-BASED ATTACKS

These attacks are carried out directly on a target model assuming query access to the output probabilities. An untargeted query-based attack with no query reduction using Single Step Finite Differences can be carried out on Model A as follows:

python query_based_attack.py models/modelA --method=query_based_un

A parameter --delta can be used to control the perturbations in input space used to estimate gradients. It is set to a default value of 0.01. To run a targeted version, set the --method option to 'query_based'. The_untargeted Iterative Finite Differences_ attack can be run as follows:

python query_based_attack.py models/modelA --method=query_based_un_iter

The number of iterations is set using the --num_iter flag and the step size per iteration is set using the --beta flag. The default values of these are 40 and 0.1 respectively. Targeted attacks can be run by setting the --method option to 'query_based_iter'.

To run an attack using the technique of Simultaneous Perturbation Stochastic Approximation (SPSA), the --method option is set to 'spsa_iter' for targeted attacks and to 'spsa_un_iter' for untargeted attacks.

USING QUERY-REDUCTION TECHNIQUES

To reduce the number of queries, two methods are implemented in the query_based_attack.py script. These can be used along with any of the Finite Difference methods ('query_based', 'query_based_un', 'query_based_iter' and 'query_based_un_iter') To use the Random Grouping method with 8 pixels grouped together, for example, with the untargeted Single Step Gradient Estimation method, run

python query_based_attack.py models/modelA --method=query_based_un --group_size=8

Similarly, to use the PCA component based query reduction with 100 components, for example, with the same attack as above, run

python query_based_attack.py models/modelA --method=query_based_un --num_comp=100

These query-reduction techniques can be used with targeted, untargeted, Single-Step and Iterative Gradient Estimation methods.

ATTACKS ON CLARIFAI

To run attacks on models hosted by Clarifai, first follow the instructions given here to install their Python client. You will need to obtain your own API key and set it using clarifai config. The two models currently supported for attack are the 'moderation' and 'nsfw-v1.0' models. To obtain an adversarial example for the 'moderation' model starting with my_image.jpg, run the attack_clarifai.py script as follows:

python attack_clarifai.py my_image --target_model=moderation

The default attack used is Gradient Estimation with query reduction using Random Grouping. The available options are the magnitude of perturbation (--eps), number of iterations (--num_iter), group size for random grouping (--group_size) and gradient estimation parameter (--delta). Only the logit loss is used since it is found to perform well. The target image must be an RGB image in the JPEG format. The Resizing_clarifai.ipynb notebook allows for interactive re-sizing of images in case the target image is too large.

CONTACT

This repository is under active development. Questions and suggestions can be sent to abhagoji@princeton.edu