Syft scan in offline mode is slow

[KeylinxTobias]

We are having our build environment disconnected from Internet for security reasons and want to be able to produce an non enriched SBOM using Syft. However when running Syft, the scanning is very slow. Using the verbose logging and we can track that it is some dll's that take a lot of time. We have checked the configuration options and tried to disable as much as possible but it still does not go well. It seems that when scanning each file, Syft tries to go out on Internet and check for something and then times out? A common solution for us can sometimes take about an hour to produce the SBOM. When using other scanners like Trivy, we are down to seconds.

We are mainly using nuget packages in our solution and are using windows servers for our build environment.

How to reproduce:

1. Download syft.exe and files, copy it to an offline machine
2. Run a scan on a dotnet solution

Thanks in advance.

[wagoodman]

An initial glance shows that what's taking time is the dotnet-portable-executable-cataloger. The dotnet-deps-cataloger is clocking in rather fast (only seconds for large projects such as dotnet/sdk and dotnet/roslyn. On the other hand, taking a look at specifically the SDK project after running ./build.sh we get a lot of DLLs:

find . | grep dll | wc -l                       
   36335

Now the time to read that many DLLs make sense, however, looking at the raw syft results I think a few things need to be verified:

❯ time syft .     
 ✔ Indexed file system                                                                                                                                                                                    .
 ✔ Cataloged contents                                                                                                                      cdb4ee2aea69cc6a83331bbe96dc2caa9a299d21329efb0336fc02a82e1839a8
   ├── ✔ Packages                        [46,897 packages]  
   ├── ✔ File digests                    [36,540 files]  
   ├── ✔ File metadata                   [36,540 locations]  
   └── ✔ Executables                     [36,689 executables]  
...
System.Diagnostics.DiagnosticSource                                            9.0.24.52809                                                       dotnet                  (+1 duplicate)      
System.Diagnostics.EventLog                                                    10.0.0-alpha.1.24531.8                                             dotnet                  (+2 duplicates)     
System.Diagnostics.EventLog                                                    10.0.0-alpha.1.24565.3                                             dotnet                  (+102 duplicates)   
System.Diagnostics.EventLog                                                    10.0.24.53005                                                      dotnet                  (+3 duplicates)     
System.Diagnostics.EventLog                                                    10.0.24.53108                                                      dotnet                  (+7 duplicates)     
System.Diagnostics.EventLog                                                    10.0.24.55105                                                      dotnet                  (+3 duplicates)     
System.Diagnostics.EventLog                                                    10.0.24.56503                                                      dotnet                  (+145 duplicates)   
System.Diagnostics.EventLog                                                    7.0.0                                                              dotnet                  (+30 duplicates)    
System.Diagnostics.EventLog                                                    8.0.0                                                              dotnet                  (+5 duplicates)     
...
syft .  173.88s user 25.37s system 119% cpu 2:46.38 total

I see a lot of packages (46,897!) and a lot of them have multiple duplicates (some in the hundreds!). We try to keep distinct project dependency graphs, so it might be possible that this is correct, but I think it would be worth double checking this result too.

Back to the topic at hand: performance... I don't see how we can scan that many DLLs in only seconds, so that doesn't seem like the right answer here. The deps.json cataloger also has a lot to work with one a build has been performed:

$ find . | grep deps.json | wc -l
     354

And when we ignore DLLs (thus look purely at the deps.json) we see much better performance:

❯ time syft . --exclude '**/*.dll'                                    
 ✔ Indexed file system                                                                                                                                                                                    .
 ✔ Cataloged contents                                                                                                                      cdb4ee2aea69cc6a83331bbe96dc2caa9a299d21329efb0336fc02a82e1839a8
   ├── ✔ Packages                        [10,787 packages]  
   ├── ✔ File digests                    [430 files]  
   ├── ✔ File metadata                   [430 locations]  
   └── ✔ Executables                     [497 executables]  
[0000]  WARN no explicit name and version provided for directory source, deriving artifact ID from the given path (which is not ideal)
NAME                                                                           VERSION                     TYPE                                      
.                                                                              10.0.100-dev                dotnet                  (+7 duplicates)    
.NET Host                                                                      6.0.4                       dotnet                                     
Argon                                                                          0.17.0                      dotnet                  (+1 duplicate)     
ArgumentForwarding.Tests                                                       10.0.100-dev                dotnet                                     
ArgumentsReflector                                                             10.0.100-dev                dotnet                  (+2 duplicates)    
Castle.Core                                                                    5.1.1                       dotnet                  (+16 duplicates)   
ConsoleDemoWithCasing                                                          1.0.0                       dotnet                  (+2 duplicates)    
DiffEngine                                                                     15.4.2                      dotnet                  (+1 duplicate)     
DiffPlex                                                                       1.5.0                       dotnet                                     
DiffPlex                                                                       1.7.2                       dotnet                  (+1 duplicate)     
DotNetWatchTasks                                                               10.0.100-dev                dotnet                  (+1 duplicate)     
DumpMinitool                                                                   17.1300.24.52301            dotnet                                     
DumpMinitool                                                                   17.1300.24.56301            dotnet                  (+4 duplicates)    
...
xunit.extensibility.core                                                       2.9.2                       dotnet                  (+50 duplicates)   
xunit.extensibility.execution                                                  2.9.2                       dotnet                  (+50 duplicates)   
xunit.runner.console                                                           2.9.2                       dotnet                  (+46 duplicates)   
xunit.runner.reporters                                                         2.9.2                       dotnet                  (+46 duplicates)   
xunit.runner.utility                                                           2.9.2                       dotnet                  (+46 duplicates)   
xunit.runner.visualstudio                                                      2.8.2                       dotnet                  (+46 duplicates)
A newer version of syft is available for download: 1.15.0 (installed version is 1.14.2)
syft . --exclude '**/*.dll'  7.50s user 3.08s system 99% cpu 10.665 total

As a workaround @KeylinxTobias can you try out running syft with --exclude '**/*.dll' and report back if it is both performant and accurate for you?

Side note: I wonder if we should have a *.csproj cataloger? I'm not a dotnet developer, so this might be a bad suggestion for a syft enhancement.

[kzantow]

There is a request for a csproj cataloger: #1522

[TimBrown1611]

is this issue happens on windows OS?

[popey]

@TimBrown1611 I don't believe this is a windows specific issue, no. GIven @wagoodman ran ./build.sh, and as a fine upstanding gentleman, I presume he's running Linux (or macos). The confusion often comes when talking about DLL files, as DotNet on non-Windows operating system also uses DLLs for shared libraries.