Fuzz introspector
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Project coverage

Table of contents

Project overview: ntlm2
High level conclusions
Reachability and coverage overview
Fuzzers overview
Project functions overview
Fuzzer details
Fuzzer: fuzz_core
Call tree
Runtime coverage analysis
Files reached
Fuzzer: fuzz_auth
Call tree
Fuzz blockers
Runtime coverage analysis
Files reached
Analyses and suggestions
Optimal target analysis
Remaining optimal interesting functions
All functions overview
Fuzz engine guidance
/src/fuzz_core.py
Dictionary
Fuzzer function priority
/src/fuzz_auth.py
Dictionary
Fuzzer function priority
Runtime coverage analysis
Complex functions with low coverage
Files and Directories in report
Files in report
Directories in report
Metadata section
Report generation date: 2025-07-18

Project overview: ntlm2

High level conclusions

Reachability and coverage overview

Functions statically reachable by fuzzers
16.0%
46 / 288
Cyclomatic complexity statically reachable by fuzzers
17.0%
170 / 996
Runtime code coverage of functions
14.0%
40 / 288

Fuzzers overview

Fuzzer Fuzzer filename Functions Reached Functions unreached Fuzzer depth Files reached Basic blocks reached Cyclomatic complexity Details
fuzz_core /src/fuzz_core.py 13 676 3 3 4 38 fuzz_core.py
fuzz_auth /src/fuzz_auth.py 167 615 8 9 86 529 fuzz_auth.py

Project functions overview

The following table shows data about each function in the project. The functions included in this table correspond to all functions that exist in the executables of the fuzzers. As such, there may be functions that are from third-party libraries.

For further technical details on the meaning of columns in the below table, please see the Glossary .

Func name Functions filename Args Function call depth Reached by Fuzzers Runtime reached by Fuzzers Combined reached by Fuzzers Fuzzers runtime hit Func lines hit % I Count BB Count Cyclomatic complexity Functions reached Reached by functions Accumulated cyclomatic complexity Undiscovered complexity

Fuzzer details

Fuzzer: fuzz_core

Call tree

The calltree shows the control flow of the fuzzer. This is overlaid with coverage information to display how much of the potential code a fuzzer can reach is in fact covered at runtime. In the following there is a link to a detailed calltree visualisation as well as a bitmap showing a high-level view of the calltree. For further information about these topics please see the glossary for full calltree and calltree overview

Full calltree

Call tree overview bitmap:

The distribution of callsites in terms of coloring is
Color Runtime hitcount Callsite count Percentage
red 0 0 0.0%
gold [1:9] 0 0.0%
yellow [10:29] 0 0.0%
greenyellow [30:49] 0 0.0%
lawngreen 50+ 16 100.%
All colors 16 100

Runtime coverage analysis

Covered functions
89
Functions that are reachable but not covered
8
Reachable functions
13
Percentage of reachable functions covered
38.46%
NB: The sum of covered functions and functions that are reachable but not covered need not be equal to Reachable functions . This is because the reachability analysis is an approximation and thus at runtime some functions may be covered that are not included in the reachability analysis. This is a limitation of our static analysis capabilities.
Warning: The number of covered functions are larger than the number of reachable functions. This means that there are more functions covered at runtime than are extracted using static analysis. This is likely a result of the static analysis component failing to extract the right call graph or the coverage runtime being compiled with sanitizers in code that the static analysis has not analysed. This can happen if lto/gold is not used in all places that coverage instrumentation is used.
Function name source code lines source lines hit percentage hit

Files reached

filename functions hit
/ 1
...fuzz_core 5
requests_ntlm2.core 7

Fuzzer: fuzz_auth

Call tree

The calltree shows the control flow of the fuzzer. This is overlaid with coverage information to display how much of the potential code a fuzzer can reach is in fact covered at runtime. In the following there is a link to a detailed calltree visualisation as well as a bitmap showing a high-level view of the calltree. For further information about these topics please see the glossary for full calltree and calltree overview

Full calltree

Call tree overview bitmap:

The distribution of callsites in terms of coloring is
Color Runtime hitcount Callsite count Percentage
red 0 290 98.9%
gold [1:9] 0 0.0%
yellow [10:29] 0 0.0%
greenyellow [30:49] 0 0.0%
lawngreen 50+ 3 1.02%
All colors 293 100

Fuzz blockers

The following nodes represent call sites where fuzz blockers occur.

Amount of callsites blocked Calltree index Parent function Callsite Largest blocked function
288 4 ...fuzz_auth.ServerThread.__init__ call site: 00004 requests.sessions.Session.get
2 0 EP call site: 00000 ...fuzz_auth.ServerThread.__init__

Runtime coverage analysis

Covered functions
90
Functions that are reachable but not covered
162
Reachable functions
167
Percentage of reachable functions covered
2.99%
NB: The sum of covered functions and functions that are reachable but not covered need not be equal to Reachable functions . This is because the reachability analysis is an approximation and thus at runtime some functions may be covered that are not included in the reachability analysis. This is a limitation of our static analysis capabilities.
Function name source code lines source lines hit percentage hit

Files reached

filename functions hit
/ 1
...fuzz_auth 10
requests.sessions 85
requests.models 6
requests.cookies 28
requests.utils 50
requests.hooks 9
requests._internal_utils 3
requests.auth 8

Analyses and suggestions

Optimal target analysis

Remaining optimal interesting functions

The following table shows a list of functions that are optimal targets. Optimal targets are identified by finding the functions that in combination, yield a high code coverage.

Func name Functions filename Arg count Args Function depth hitcount instr count bb count cyclomatic complexity Reachable functions Incoming references total cyclomatic complexity Unreached complexity
requests.adapters.HTTPAdapter.send requests.adapters 7 ['N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A'] 5 0 3 10 7 80 0 264 168
requests.models.PreparedRequest.prepare_body requests.models 4 ['N/A', 'N/A', 'N/A', 'N/A'] 3 0 2 10 7 51 11 172 144
requests_ntlm2.requests_ntlm2.HttpNtlmAuth.response_hook requests_ntlm2.requests_ntlm2 3 ['N/A', 'N/A', 'N/A'] 5 0 1 4 5 57 0 183 139
requests.auth.HTTPDigestAuth.handle_401 requests.auth 3 ['N/A', 'N/A', 'N/A'] 4 0 7 3 4 38 0 126 102
requests_ntlm2.connection.VerifiedHTTPSConnection._tunnel requests_ntlm2.connection 1 ['N/A'] 4 0 18 10 7 50 0 163 78
requests.utils.extract_zipped_paths requests.utils 1 ['N/A'] 2 0 2 5 5 16 1 53 50
requests.models.PreparedRequest.prepare_url requests.models 3 ['N/A', 'N/A', 'N/A'] 3 0 1 12 8 39 11 129 35
requests.models.Response.iter_lines requests.models 4 ['N/A', 'N/A', 'N/A', 'N/A'] 3 0 3 4 5 12 0 44 35

Implementing fuzzers that target the above functions will improve reachability such that it becomes:

Functions statically reachable by fuzzers
38.0%
108 / 288
Cyclomatic complexity statically reachable by fuzzers
42.0%
423 / 996

All functions overview

If you implement fuzzers for these functions, the status of all functions in the project will be:

Func name Functions filename Args Function call depth Reached by Fuzzers Runtime reached by Fuzzers Combined reached by Fuzzers Fuzzers runtime hit Func lines hit % I Count BB Count Cyclomatic complexity Functions reached Reached by functions Accumulated cyclomatic complexity Undiscovered complexity

Fuzz engine guidance

This sections provides heuristics that can be used as input to a fuzz engine when running a given fuzz target. The current focus is on providing input that is usable by libFuzzer.

/src/fuzz_core.py

Dictionary

Use this with the libFuzzer -dict=DICT.file flag


/src/fuzz_auth.py

Dictionary

Use this with the libFuzzer -dict=DICT.file flag


Fuzzer function priority

Use one of these functions as input to libfuzzer with flag: -focus_function name 

-focus_function=['...fuzz_auth.ServerThread.__init__']

Runtime coverage analysis

This section shows analysis of runtime coverage data.

For futher technical details on how this section is generated, please see the Glossary .

Complex functions with low coverage

Func name Function total lines Lines covered at runtime percentage covered Reached by fuzzers
ntlm_auth.messages.ChallengeMessage 232 66 28.44% ['fuzz_auth', 'fuzz_core']
requests.utils.super_len 32 0 0.0% []
d.items 189 25 13.22% ['fuzz_auth', 'fuzz_core']
collections.OrderedDict.pop 234 76 32.47% ['fuzz_core']
url.append 204 60 29.41% ['fuzz_auth', 'fuzz_core']
requests.sessions.SessionRedirectMixin.resolve_redirects 50 0 0.0% ['fuzz_auth']
requests.sessions.Session.send 36 0 0.0% ['fuzz_auth']
requests.models.RequestEncodingMixin._encode_files 38 0 0.0% []
requests.models.PreparedRequest.prepare_url 39 0 0.0% []
requests.models.PreparedRequest.prepare_body 38 0 0.0% []
requests.auth.HTTPDigestAuth.build_digest_header.sha512_utf8 44 0 0.0% []
requests.adapters.HTTPAdapter.send 45 0 0.0% []
request.headers.get 108 49 45.37% ['fuzz_auth', 'fuzz_core']
urllib3.util.ssl_.create_urllib3_context.load_verify_locations 181 82 45.30% ['fuzz_auth', 'fuzz_core']
urllib3.util.retry.Retry.from_int 175 61 34.85% ['fuzz_auth', 'fuzz_core']
r.register_hook 244 87 35.65% ['fuzz_auth', 'fuzz_core']
urllib3.contrib.socks.SOCKSProxyManager 83 9 10.84% ['fuzz_auth', 'fuzz_core']
urllib3.fields.RequestField.make_multipart 93 20 21.50% ['fuzz_auth', 'fuzz_core']
urllib3.filepost.encode_multipart_formdata 37 13 35.13% ['fuzz_auth', 'fuzz_core']
requests_ntlm2.requests_ntlm2.HttpNtlmAuth.retry_using_http_ntlm_auth 32 0 0.0% []
requests_ntlm2.connection.VerifiedHTTPSConnection._tunnel 68 5 7.352% ['fuzz_auth', 'fuzz_core']
response.connection.send 138 34 24.63% ['fuzz_core']
collections.abc.MutableMapping.url.retry_using_http_ntlm_auth 234 76 32.47% ['fuzz_auth']

Files and Directories in report

This section shows which files and directories are considered in this report. The main reason for showing this is fuzz introspector may include more code in the reasoning than is desired. This section helps identify if too many files/directories are included, e.g. third party code, which may be irrelevant for the threat model. In the event too much is included, fuzz introspector supports a configuration file that can exclude data from the report. See the following link for more information on how to create a config file: link

Files in report

Source file Reached by Covered by
...fuzz_core ['fuzz_core'] []
[] []
requests.certs [] []
requests_ntlm2.core ['fuzz_core'] []
platform [] []
requests.exceptions [] []
requests.api [] []
requests.packages [] []
requests_ntlm2.requests_ntlm2 [] []
select [] []
json [] []
requests._internal_utils ['fuzz_auth'] []
threading [] []
requests.__version__ [] []
certifi [] []
urllib3 [] []
requests.models ['fuzz_auth'] []
requests.cookies ['fuzz_auth'] []
socket [] []
datetime [] []
requests.status_codes [] []
requests.compat [] []
requests.sessions ['fuzz_auth'] []
requests.adapters [] []
hashlib [] []
ntlm_auth [] []
zipfile [] []
re [] []
base64 [] []
requests.help [] []
calendar [] []
requests_ntlm2.connection [] []
idna [] []
atheris [] []
struct [] []
requests.auth ['fuzz_auth'] []
logging [] []
cryptography [] []
dummy_threading [] []
binascii [] []
copy [] []
importlib [] []
requests [] []
requests.structures [] []
requests.utils ['fuzz_auth'] []
collections [] []
simplejson [] []
charset_normalizer [] []
requests_ntlm2.adapters [] []
winreg [] []
tempfile [] []
netrc [] []
warnings [] []
requests_ntlm2 [] []
...fuzz_auth ['fuzz_auth'] []
[] []
requests.hooks ['fuzz_auth'] []
time [] []
os [] []
requests_ntlm2.dance [] []
http [] []
chardet [] []
urllib [] []
codecs [] []

Directories in report

Directory

Metadata section

This sections shows the raw data that is used to produce this report. This is mainly used for further processing and developer debugging.

Fuzzer Calltree file Program data file Coverage file
fuzz_core fuzzerLogFile-fuzz_core.data fuzzerLogFile-fuzz_core.data.yaml all_cov.json
fuzz_auth fuzzerLogFile-fuzz_auth.data fuzzerLogFile-fuzz_auth.data.yaml all_cov.json