# MOpt(imized) AFL by <puppet@zju.edu.cn>

### 1. Description
MOpt-AFL is a AFL-based fuzzer that utilizes a customized Particle Swarm
Optimization (PSO) algorithm to find the optimal selection probability
distribution of operators with respect to fuzzing effectiveness.
More details can be found in the technical report.

### 2. Cite Information
Chenyang Lv, Shouling Ji, Chao Zhang, Yuwei Li, Wei-Han Lee, Yu Song and
Raheem Beyah, MOPT: Optimized Mutation Scheduling for Fuzzers,
USENIX Security 2019. 

### 3. Seed Sets
We open source all the seed sets used in the paper 
"MOPT: Optimized Mutation Scheduling for Fuzzers".

### 4. Experiment Results
The experiment results can be found in 
https://drive.google.com/drive/folders/184GOzkZGls1H2NuLuUfSp9gfqp1E2-lL?usp=sharing.  We only open source the crash files since the space is limited. 

### 5. Technical Report
MOpt_TechReport.pdf is the technical report of the paper 
"MOPT: Optimized Mutation Scheduling for Fuzzers", which contains more deatails.

### 6. Parameter Introduction
Most important, you must add the parameter `-L` (e.g., `-L 0`) to launch the
MOpt scheme. 
<br>`-L` controls the time to move on to the pacemaker fuzzing mode.
<br>`-L t:` when MOpt-AFL finishes the mutation of one input, if it has not
discovered any new unique crash or path for more than t min, MOpt-AFL will
enter the pacemaker fuzzing mode. 
<br>Setting 0 will enter the pacemaker fuzzing mode at first, which is
recommended in a short time-scale evaluation. 

Other important parameters can be found in afl-fuzz.c, for instance, 
<br>`swarm_num:` the number of the PSO swarms used in the fuzzing process.
<br>`period_pilot:` how many times MOpt-AFL will execute the target program in the pilot fuzzing module, then it will enter the core fuzzing module. 
<br>`period_core:` how many times MOpt-AFL will execute the target program in the core fuzzing module, then it will enter the PSO updating module. 
<br>`limit_time_bound:` control how many interesting test cases need to be found before MOpt-AFL quits the pacemaker fuzzing mode and reuses the deterministic stage. 
0 < `limit_time_bound` < 1, MOpt-AFL-tmp.  `limit_time_bound` >= 1, MOpt-AFL-ever. 

Having fun with MOpt in AFL!