Headline
CVE-2022-31588: Python : Flask Path Traversal Vulnerability · Issue #669 · github/securitylab
The zippies/testplatform repository through 2016-07-19 on GitHub allows absolute path traversal because the Flask send_file function is used unsafely.
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porcupineyhairs pushed a commit to porcupineyhairs/flask-mongo-skel that referenced this issue
Apr 28, 2022
A path traversal attack (also known as directory traversal) aims to access files and directories that are stored outside the web root folder. By manipulating variables that reference files with “dot-dot-slash (…/)” sequences and its variations or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system including application source code or configuration and critical system files. This attack is also known as “dot-dot-slash”, “directory traversal”, “directory climbing” and “backtracking”.
Root Cause Analysis
Passing untrusted input to `flask.send_file`can lead to path traversal attacks.
In this case, the problems occurs due to the following code : https://github.com/piaoyunsoft/bt_lnmp/blob/fa49519b04586a00e76c105e7ce1da36eadf6922/www/server/panel/BTPanel/__init__.py#L858
Here, the `filename` parameter is attacker controlled and is used as the filename passed to the `send_file` call. This leads to a path traversal attack.
Remediation
This can be fixed by preventing flow of untrusted data to the vulnerable `send_file` function. In case the application logic necessiates this behaviour, one can either use the `flask.safe_join` to join untrusted paths or replace `flask.send_file` calls with `flask.send_from_directory` calls.
References
* [OWASP Path Traversal](https://owasp.org/www-community/attacks/Path_Traversal) * github/securitylab#669
This bug was found using *[CodeQL by Github](codeql.github.com/)*
porcupineyhairs pushed a commit to porcupineyhairs/sphere that referenced this issue
Apr 28, 2022
A path traversal attack (also known as directory traversal) aims to access files and directories that are stored outside the web root folder. By manipulating variables that reference files with “dot-dot-slash (…/)” sequences and its variations or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system including application source code or configuration and critical system files. This attack is also known as “dot-dot-slash”, “directory traversal”, “directory climbing” and “backtracking”.
Root Cause Analysis
Passing untrusted input to `flask.send_file`can lead to path traversal attacks.
In this case, the problems occurs due to the following code : https://github.com/piaoyunsoft/bt_lnmp/blob/fa49519b04586a00e76c105e7ce1da36eadf6922/www/server/panel/BTPanel/__init__.py#L858
Here, the `filename` parameter is attacker controlled and is used as the filename passed to the `send_file` call. This leads to a path traversal attack.
Remediation
This can be fixed by preventing flow of untrusted data to the vulnerable `send_file` function. In case the application logic necessiates this behaviour, one can either use the `flask.safe_join` to join untrusted paths or replace `flask.send_file` calls with `flask.send_from_directory` calls.
References
* [OWASP Path Traversal](https://owasp.org/www-community/attacks/Path_Traversal) * github/securitylab#669
This bug was found using *[CodeQL by Github](codeql.github.com/)*
porcupineyhairs pushed a commit to porcupineyhairs/glance that referenced this issue
Apr 28, 2022
A path traversal attack (also known as directory traversal) aims to access files and directories that are stored outside the web root folder. By manipulating variables that reference files with “dot-dot-slash (…/)” sequences and its variations or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system including application source code or configuration and critical system files. This attack is also known as “dot-dot-slash”, “directory traversal”, “directory climbing” and “backtracking”.
Root Cause Analysis
Passing untrusted input to `flask.send_file`can lead to path traversal attacks.
In this case, the problems occurs due to the following code : https://github.com/piaoyunsoft/bt_lnmp/blob/fa49519b04586a00e76c105e7ce1da36eadf6922/www/server/panel/BTPanel/__init__.py#L858
Here, the `filename` parameter is attacker controlled and is used as the filename passed to the `send_file` call. This leads to a path traversal attack.
Remediation
This can be fixed by preventing flow of untrusted data to the vulnerable `send_file` function. In case the application logic necessiates this behaviour, one can either use the `flask.safe_join` to join untrusted paths or replace `flask.send_file` calls with `flask.send_from_directory` calls.
References
* [OWASP Path Traversal](https://owasp.org/www-community/attacks/Path_Traversal) * github/securitylab#669
This bug was found using *(CodeQL by Github)[https://codeql.github.com/]*
porcupineyhairs pushed a commit to porcupineyhairs/pyathenastack that referenced this issue
Apr 28, 2022
A path traversal attack (also known as directory traversal) aims to access files and directories that are stored outside the web root folder. By manipulating variables that reference files with “dot-dot-slash (…/)” sequences and its variations or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system including application source code or configuration and critical system files. This attack is also known as “dot-dot-slash”, “directory traversal”, “directory climbing” and “backtracking”.
Root Cause Analysis
Passing untrusted input to `flask.send_file`can lead to path traversal attacks.
In this case, the problems occurs due to the following code : https://github.com/piaoyunsoft/bt_lnmp/blob/fa49519b04586a00e76c105e7ce1da36eadf6922/www/server/panel/BTPanel/__init__.py#L858
Here, the `filename` parameter is attacker controlled and is used as the filename passed to the `send_file` call. This leads to a path traversal attack.
Remediation
This can be fixed by preventing flow of untrusted data to the vulnerable `send_file` function. In case the application logic necessiates this behaviour, one can either use the `flask.safe_join` to join untrusted paths or replace `flask.send_file` calls with `flask.send_from_directory` calls.
References
* [OWASP Path Traversal](https://owasp.org/www-community/attacks/Path_Traversal) * github/securitylab#669
This bug was found using *[CodeQL by Github](https://codeql.github.com/)*
porcupineyhairs pushed a commit to porcupineyhairs/homepage that referenced this issue
Apr 28, 2022
A path traversal attack (also known as directory traversal) aims to access files and directories that are stored outside the web root folder. By manipulating variables that reference files with “dot-dot-slash (…/)” sequences and its variations or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system including application source code or configuration and critical system files. This attack is also known as “dot-dot-slash”, “directory traversal”, “directory climbing” and “backtracking”.
Root Cause Analysis
The `os.path.join` call is unsafe for use with untrusted input. When the `os.path.join` call encounters an absolute path, it ignores all the parameters it has encountered till that point and starts working with the new absolute path. Please see the example below. ```
import os.path static = “path/to/mySafeStaticDir” malicious = “/…/…/…/…/…/etc/passwd” os.path.join(t,malicious) ‘/…/…/…/…/…/etc/passwd’ ``` Since the “malicious” parameter represents an absolute path, the result of `os.path.join` ignores the static directory completely. Hence, untrusted input is passed via the `os.path.join` call to `flask.send_file` can lead to path traversal attacks.
In this case, the problems occurs due to the following code : https://github.com/nrlakin/homepage/blob/82ffb967f370bfe84b6e954a59022f37f4f105c1/home/frontend/views.py#L78
Here, the `filename` parameter is attacker controlled. This parameter passes through the unsafe `os.path.join` call making the effective directory and filename passed to the `send_file` call attacker controlled. This leads to a path traversal attack.
Proof of Concept
The bug can be verified using a proof of concept similar to the one shown below.
``` curl --path-as-is ‘http://<domain>/download//…/…/…/…/etc/passwd"’ ```
Remediation
This can be fixed by preventing flow of untrusted data to the vulnerable `send_file` function. In case the application logic necessiates this behaviour, one can either use the `flask.safe_join` to join untrusted paths or replace `flask.send_file` calls with `flask.send_from_directory` calls.
References
* [OWASP Path Traversal](https://owasp.org/www-community/attacks/Path_Traversal) * github/securitylab#669
This bug was found using *[CodeQL by Github](https://codeql.github.com/)*
porcupineyhairs pushed a commit to porcupineyhairs/equanimity that referenced this issue
Apr 28, 2022
A path traversal attack (also known as directory traversal) aims to access files and directories that are stored outside the web root folder. By manipulating variables that reference files with “dot-dot-slash (…/)” sequences and its variations or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system including application source code or configuration and critical system files. This attack is also known as “dot-dot-slash”, “directory traversal”, “directory climbing” and “backtracking”.
Root Cause Analysis
The `os.path.join` call is unsafe for use with untrusted input. When the `os.path.join` call encounters an absolute path, it ignores all the parameters it has encountered till that point and starts working with the new absolute path. Please see the example below. ```
import os.path static = “path/to/mySafeStaticDir” malicious = “/…/…/…/…/…/etc/passwd” os.path.join(t,malicious) ‘/…/…/…/…/…/etc/passwd’ ``` Since the “malicious” parameter represents an absolute path, the result of `os.path.join` ignores the static directory completely. Hence, untrusted input is passed via the `os.path.join` call to `flask.send_file` can lead to path traversal attacks.
In this case, the problems occurs due to the following code : https://github.com/AFDudley/equanimity/blob/16862abb282f174ceb7ca297c956565fcfb188ad/server/views/frontend.py#L25
Here, the `path` parameter is attacker controlled. This parameter passes through the unsafe `os.path.join` call making the effective directory and filename passed to the `send_file` call attacker controlled. This leads to a path traversal attack.
Proof of Concept
The bug can be verified using a proof of concept similar to the one shown below.
``` curl --path-as-is ‘http://<domain>/js//…/…/…/…/etc/passwd"’ ```
Remediation
This can be fixed by preventing flow of untrusted data to the vulnerable `send_file` function. In case the application logic necessiates this behaviour, one can either use the `flask.safe_join` to join untrusted paths or replace `flask.send_file` calls with `flask.send_from_directory` calls.
References
* [OWASP Path Traversal](https://owasp.org/www-community/attacks/Path_Traversal) * github/securitylab#669
This bug was found using *[CodeQL by Github](https://codeql.github.com/)*
porcupineyhairs pushed a commit to porcupineyhairs/monorepo that referenced this issue
May 3, 2022
A path traversal attack (also known as directory traversal) aims to access files and directories that are stored outside the web root folder. By manipulating variables that reference files with “dot-dot-slash (…/)” sequences and its variations or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system including application source code or configuration and critical system files. This attack is also known as “dot-dot-slash”, “directory traversal”, “directory climbing” and “backtracking”.
Common Weakness Enumeration category
CWE - 36
Root Cause Analysis
The `os.path.join` call is unsafe for use with untrusted input. When the `os.path.join` call encounters an absolute path, it ignores all the parameters it has encountered till that point and starts working with the new absolute path. Please see the example below. ```
import os.path static = “path/to/mySafeStaticDir” malicious = “/…/…/…/…/…/etc/passwd” os.path.join(t,malicious) ‘/…/…/…/…/…/etc/passwd’ ``` Since the “malicious” parameter represents an absolute path, the result of `os.path.join` ignores the static directory completely. Hence, untrusted input is passed via the `os.path.join` call to `flask.send_file` can lead to path traversal attacks.
In this case, the problems occurs due to the following code : https://github.com/cinemaproject/monorepo/blob/d6a952c2ed9187a0032293fce0a492358edefe23/model_server/app/main.py#L34
Here, the `path` parameter is attacker controlled. This parameter passes through the unsafe `os.path.join` call making the effective directory and filename passed to the `send_file` call attacker controlled. This leads to a path traversal attack.
Proof of Concept
The bug can be verified using a proof of concept similar to the one shown below.
``` curl --path-as-is ‘http://<domain>/api/images//…/…/…/…/etc/passwd"’ ```
Remediation
This can be fixed by preventing flow of untrusted data to the vulnerable `send_file` function. In case the application logic necessiates this behaviour, one can either use the `werkzeug.utils.safe_join` to join untrusted paths or replace `flask.send_file` calls with `flask.send_from_directory` calls.
Common Vulnerability Scoring System Vector
The attack can be carried over the network. A complex non-standard configuration or a specialized condition is not required for the attack to be successfully conducted. There is no user interaction required for successful execution. The attack can affect components outside the scope of the target module. The attack can be used to gain access to confidential files like passwords, login credentials and other secrets. It cannot be directly used to affect a change on a system resource. Hence has limited to no impact on integrity. Using this attack vector a attacker may make multiple requests for accessing huge files such as a database. This can lead to a partial system denial service. However, the impact on availability is quite low in this case. Taking this account an appropriate CVSS v3.1 vector would be
(AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L)[https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L&version=3.1]
This gives it a base score of 9.3/10 and a severity rating of critical.
References
* [OWASP Path Traversal](https://owasp.org/www-community/attacks/Path_Traversal) * github/securitylab#669
This bug was found using *[CodeQL by Github](https://codeql.github.com/)*
porcupineyhairs pushed a commit to porcupineyhairs/csm that referenced this issue
May 3, 2022
A path traversal attack (also known as directory traversal) aims to access files and directories that are stored outside the web root folder. By manipulating variables that reference files with “dot-dot-slash (…/)” sequences and its variations or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system including application source code or configuration and critical system files. This attack is also known as “dot-dot-slash”, “directory traversal”, “directory climbing” and “backtracking”.
Common Weakness Enumeration category
CWE - 36
Root Cause Analysis
The `os.path.join` call is unsafe for use with untrusted input. When the `os.path.join` call encounters an absolute path, it ignores all the parameters it has encountered till that point and starts working with the new absolute path. Please see the example below. ```
import os.path static = “path/to/mySafeStaticDir” malicious = “/…/…/…/…/…/etc/passwd” os.path.join(t,malicious)
‘/…/…/…/…/…/etc/passwd’ ``` Since the “malicious” parameter represents an absolute path, the result of `os.path.join` ignores the static directory completely. Hence, untrusted input is passed via the `os.path.join` call to `flask.send_file` can lead to path traversal attacks.
In this case, the problems occurs due to the following code : https://github.com/csm-aut/csm/blob/b38843a6cdc19a406e6f709c53767bdaaa2fef96/csmserver/views/log.py#L284
Here, the `file_path` parameter is attacker controlled. This parameter passes through the unsafe `os.path.join` call making the effective directory and filename passed to the `send_file` call attacker controlled. This leads to a path traversal attack.
Proof of Concept
The bug can be verified using a proof of concept similar to the one shown below.
``` curl --path-as-is ‘http://<domain>/download_doc_central_log?file_path=…/…/…/…/…/…/…/etc/passwd"’ ```
Remediation
This can be fixed by preventing flow of untrusted data to the vulnerable `send_file` function. In case the application logic necessiates this behaviour, one can either use the `werkzeug.utils.safe_join` to join untrusted paths or replace `flask.send_file` calls with `flask.send_from_directory` calls.
Common Vulnerability Scoring System Vector
The attack can be carried over the network. A complex non-standard configuration or a specialized condition is not required for the attack to be successfully conducted. There is no user interaction required for successful execution. The attack can affect components outside the scope of the target module. The attack can be used to gain access to confidential files like passwords, login credentials and other secrets. It cannot be directly used to affect a change on a system resource. Hence has limited to no impact on integrity. Using this attack vector a attacker may make multiple requests for accessing huge files such as a database. This can lead to a partial system denial service. However, the impact on availability is quite low in this case. Taking this account an appropriate CVSS v3.1 vector would be
(AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L)[https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L&version=3.1]
This gives it a base score of 9.3/10 and a severity rating of critical.
References
* [OWASP Path Traversal](https://owasp.org/www-community/attacks/Path_Traversal) * github/securitylab#669
This bug was found using *[CodeQL by Github](https://codeql.github.com/)*
porcupineyhairs pushed a commit to porcupineyhairs/cilantro that referenced this issue
May 3, 2022
A path traversal attack (also known as directory traversal) aims to access files and directories that are stored outside the web root folder. By manipulating variables that reference files with “dot-dot-slash (…/)” sequences and its variations or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system including application source code or configuration and critical system files. This attack is also known as “dot-dot-slash”, “directory traversal”, “directory climbing” and “backtracking”.
Common Weakness Enumeration category
CWE - 36
Root Cause Analysis
The `os.path.join` call is unsafe for use with untrusted input. When the `os.path.join` call encounters an absolute path, it ignores all the parameters it has encountered till that point and starts working with the new absolute path. Please see the example below. ```
import os.path static = “path/to/mySafeStaticDir” malicious = “/…/…/…/…/…/etc/passwd” os.path.join(t,malicious) ‘/…/…/…/…/…/etc/passwd’ ``` Since the “malicious” parameter represents an absolute path, the result of `os.path.join` ignores the static directory completely. Hence, untrusted input is passed via the `os.path.join` call to `flask.send_file` can lead to path traversal attacks.
In this case, the problems occurs due to the following code : https://github.com/dainst/cilantro/blob/b421af2ffaf09403b8adb963c45c44802f833921/service/staging/staging_controller.py#L111
Here, the `path` parameter is attacker controlled. This parameter passes through the unsafe `os.path.join` call making the effective directory and filename passed to the `send_file` call attacker controlled. This leads to a path traversal attack.
Proof of Concept
The bug can be verified using a proof of concept similar to the one shown below.
``` curl --path-as-is ‘http://<domain>////…/…/…/…/etc/passwd"’ ```
Remediation
This can be fixed by preventing flow of untrusted data to the vulnerable `send_file` function. In case the application logic necessiates this behaviour, one can either use the `werkzeug.utils.safe_join` to join untrusted paths or replace `flask.send_file` calls with `flask.send_from_directory` calls.
Common Vulnerability Scoring System Vector
The attack can be carried over the network. A complex non-standard configuration or a specialized condition is not required for the attack to be successfully conducted. There is no user interaction required for successful execution. The attack can affect components outside the scope of the target module. The attack can be used to gain access to confidential files like passwords, login credentials and other secrets. It cannot be directly used to affect a change on a system resource. Hence has limited to no impact on integrity. Using this attack vector a attacker may make multiple requests for accessing huge files such as a database. This can lead to a partial system denial service. However, the impact on availability is quite low in this case. Taking this account an appropriate CVSS v3.1 vector would be
(AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L)[https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L&version=3.1]
This gives it a base score of 9.3/10 and a severity rating of critical.
References
* [OWASP Path Traversal](https://owasp.org/www-community/attacks/Path_Traversal) * github/securitylab#669
This bug was found using *[CodeQL by Github](https://codeql.github.com/)*
porcupineyhairs pushed a commit to porcupineyhairs/Fishtank that referenced this issue
May 3, 2022
A path traversal attack (also known as directory traversal) aims to access files and directories that are stored outside the web root folder. By manipulating variables that reference files with “dot-dot-slash (…/)” sequences and its variations or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system including application source code or configuration and critical system files. This attack is also known as “dot-dot-slash”, “directory traversal”, “directory climbing” and “backtracking”.
Common Weakness Enumeration category
CWE - 36
Root Cause Analysis
The `os.path.join` call is unsafe for use with untrusted input. When the `os.path.join` call encounters an absolute path, it ignores all the parameters it has encountered till that point and starts working with the new absolute path. Please see the example below. ```
import os.path static = “path/to/mySafeStaticDir” malicious = “/…/…/…/…/…/etc/passwd” os.path.join(t,malicious) ‘/…/…/…/…/…/etc/passwd’ ``` Since the “malicious” parameter represents an absolute path, the result of `os.path.join` ignores the static directory completely. Hence, untrusted input is passed via the `os.path.join` call to `flask.send_file` can lead to path traversal attacks.
In this case, the problems occurs due to the following code : https://github.com/freefood89/Fishtank/blob/bdcd8846f233d4c2d7202e2ca32a5b26080beb95/fishtankui/fishtankui.py#L100
Here, the `filename` parameter is attacker controlled. This parameter passes through the unsafe `os.path.join` call making the effective directory and filename passed to the `send_file` call attacker controlled. This leads to a path traversal attack.
Proof of Concept
The bug can be verified using a proof of concept similar to the one shown below.
``` curl --path-as-is ‘http://<domain>/images//…/…/…/…/etc/passwd"’ ```
Remediation
This can be fixed by preventing flow of untrusted data to the vulnerable `send_file` function. In case the application logic necessiates this behaviour, one can either use the `werkzeug.utils.safe_join` to join untrusted paths or replace `flask.send_file` calls with `flask.send_from_directory` calls.
Common Vulnerability Scoring System Vector
The attack can be carried over the network. A complex non-standard configuration or a specialized condition is not required for the attack to be successfully conducted. There is no user interaction required for successful execution. The attack can affect components outside the scope of the target module. The attack can be used to gain access to confidential files like passwords, login credentials and other secrets. It cannot be directly used to affect a change on a system resource. Hence has limited to no impact on integrity. Using this attack vector a attacker may make multiple requests for accessing huge files such as a database. This can lead to a partial system denial service. However, the impact on availability is quite low in this case. Taking this account an appropriate CVSS v3.1 vector would be
(AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L)[https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L&version=3.1]
This gives it a base score of 9.3/10 and a severity rating of critical.
References
* [OWASP Path Traversal](https://owasp.org/www-community/attacks/Path_Traversal) * github/securitylab#669
This bug was found using *[CodeQL by Github](https://codeql.github.com/)*
Epicus7 pushed a commit to ChaoticOnyx/OnyxForum that referenced this issue
May 4, 2022
… call
A path traversal attack (also known as directory traversal) aims to access files and directories that are stored outside the web root folder. By manipulating variables that reference files with “dot-dot-slash (…/)” sequences and its variations or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system including application source code or configuration and critical system files. This attack is also known as “dot-dot-slash”, “directory traversal”, “directory climbing” and “backtracking”.
Root Cause Analysis
The `os.path.join` call is unsafe for use with untrusted input. When the `os.path.join` call encounters an absolute path, it ignores all the parameters it has encountered till that point and starts working with the new absolute path. Please see the example below. ```
import os.path static = “path/to/mySafeStaticDir” malicious = “/…/…/…/…/…/etc/passwd” os.path.join(t,malicious) ‘/…/…/…/…/…/etc/passwd’ ``` Since the “malicious” parameter represents an absolute path, the result of `os.path.join` ignores the static directory completely. Hence, untrusted input is passed via the `os.path.join` call to `flask.send_file` can lead to path traversal attacks.
In this case, the problems occurs due to the following code : https://github.com/ChaoticOnyx/OnyxForum/blob/4077b499a1ca213f3eb55b8321a4733d83531750/modules/hub/hub/views.py#L493
Here, the `path` parameter is attacker controlled. This parameter passes through the unsafe `os.path.join` call making the effective directory and filename passed to the `send_file` call attacker controlled. This leads to a path traversal attack.
Remediation
This can be fixed by preventing flow of untrusted data to the vulnerable `send_file` function. In case the application logic necessiates this behaviour, one can either use the `flask.safe_join` to join untrusted paths or replace `flask.send_file` calls with `flask.send_from_directory` calls.
References
* [OWASP Path Traversal](https://owasp.org/www-community/attacks/Path_Traversal) * github/securitylab#669
This bug was found using *[CodeQL by Github](https://codeql.github.com/)*
Co-authored-by: Porcupiney Hairs [email protected] PR #63
egede pushed a commit to ganga-devs/ganga that referenced this issue
May 9, 2022
…2025)
A path traversal attack (also known as directory traversal) aims to access files and directories that are stored outside the web root folder. By manipulating variables that reference files with “dot-dot-slash (…/)” sequences and its variations or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system including application source code or configuration and critical system files. This attack is also known as “dot-dot-slash”, “directory traversal”, “directory climbing” and “backtracking”.
Common Weakness Enumeration category
CWE - 36
Root Cause Analysis
The `os.path.join` call is unsafe for use with untrusted input. When the `os.path.join` call encounters an absolute path, it ignores all the parameters it has encountered till that point and starts working with the new absolute path. Please see the example below. ```
import os.path static = “path/to/mySafeStaticDir” malicious = “/…/…/…/…/…/etc/passwd” os.path.join(t,malicious) ‘/…/…/…/…/…/etc/passwd’
``` Since the “malicious” parameter represents an absolute path, the result of `os.path.join` ignores the static directory completely. Hence, untrusted input is passed via the `os.path.join` call to `flask.send_file` can lead to path traversal attacks.
In this case, the problems occurs due to the following code : https://github.com/ganga-devs/ganga/blob/0c0f9e33b36ee7ead0855f1464f8d4efad26bdbc/ganga/GangaGUI/gui/routes.py#L671
Here, the `path` parameter is attacker controlled. This parameter passes through the unsafe `os.path.join` call making the effective directory and filename passed to the `send_file` call attacker controlled. This leads to a path traversal attack.
Proof of Concept
The bug can be verified using a proof of concept similar to the one shown below.
``` curl --path-as-is ‘http://<domain>/job/<int:job_id>/browse///…/…/…/…/etc/passwd"’ ```
Remediation
This can be fixed by preventing flow of untrusted data to the vulnerable `send_file` function. In case the application logic necessiates this behaviour, one can either use the `werkzeug.utils.safe_join` to join untrusted paths or replace `flask.send_file` calls with `flask.send_from_directory` calls.
Common Vulnerability Scoring System Vector
The attack can be carried over the network. A complex non-standard configuration or a specialized condition is not required for the attack to be successfully conducted. There is no user interaction required for successful execution. The attack can affect components outside the scope of the target module. The attack can be used to gain access to confidential files like passwords, login credentials and other secrets. It cannot be directly used to affect a change on a system resource. Hence has limited to no impact on integrity. Using this attack vector a attacker may make multiple requests for accessing huge files such as a database. This can lead to a partial system denial service. However, the impact on availability is quite low in this case. Taking this account an appropriate CVSS v3.1 vector would be
(AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L)[https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L&version=3.1]
This gives it a base score of 9.3/10 and a severity rating of critical.
References
* [OWASP Path Traversal](https://owasp.org/www-community/attacks/Path_Traversal) * github/securitylab#669
This bug was found using *[CodeQL by Github](https://codeql.github.com/)*
Co-authored-by: Porcupiney Hairs [email protected]
Nbobito pushed a commit to Nbobito/Piano-LED-Visualizer that referenced this issue
Jun 5, 2022
A path traversal attack (also known as directory traversal) aims to access files and directories that are stored outside the web root folder. By manipulating variables that reference files with “dot-dot-slash (…/)” sequences and its variations or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system including application source code or configuration and critical system files. This attack is also known as “dot-dot-slash”, “directory traversal”, “directory climbing” and “backtracking”.
Root Cause Analysis
The `os.path.join` call is unsafe for use with untrusted input. When the `os.path.join` call encounters an absolute path, it ignores all the parameters it has encountered till that point and starts working with the new absolute path. Please see the example below. ```
import os.path static = “path/to/mySafeStaticDir” malicious = “/…/…/…/…/…/etc/passwd” os.path.join(t,malicious) ‘/…/…/…/…/…/etc/passwd’ ``` Since the “malicious” parameter represents an absolute path, the result of `os.path.join` ignores the static directory completely. Hence, untrusted input is passed via the `os.path.join` call to `flask.send_file` can lead to path traversal attacks.
In this case, the problems occurs due to the following code : https://github.com/onlaj/Piano-LED-Visualizer/blob/6a732caa812c83a807c711f3d091af99209cae7b/webinterface/views_api.py#L970
Here, the `value` parameter is attacker controlled. This parameter passes through the unsafe `os.path.join` call making the effective directory and filename passed to the `send_file` call attacker controlled. This leads to a path traversal attack.
Proof of Concept
The bug can be verified using a proof of concept similar to the one shown below.
``` curl --path-as-is ‘http://<domain>/api/change_setting?second_value=no_reload&disable_sequence=true&value=…/…/…/…/…/…/…/etc/passwd"’ ```
Remediation
This can be fixed by preventing flow of untrusted data to the vulnerable `send_file` function. In case the application logic necessiates this behaviour, one can either use the `flask.safe_join` to join untrusted paths or replace `flask.send_file` calls with `flask.send_from_directory` calls.
References
* [OWASP Path Traversal](https://owasp.org/www-community/attacks/Path_Traversal) * github/securitylab#669
This bug was found using *[CodeQL by Github](https://codeql.github.com/)*
scaraude pushed a commit to scaraude/Piano-LED-Visualizer that referenced this issue
Jun 7, 2022
A path traversal attack (also known as directory traversal) aims to access files and directories that are stored outside the web root folder. By manipulating variables that reference files with “dot-dot-slash (…/)” sequences and its variations or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system including application source code or configuration and critical system files. This attack is also known as “dot-dot-slash”, “directory traversal”, “directory climbing” and “backtracking”.
Root Cause Analysis
The `os.path.join` call is unsafe for use with untrusted input. When the `os.path.join` call encounters an absolute path, it ignores all the parameters it has encountered till that point and starts working with the new absolute path. Please see the example below. ```
import os.path static = “path/to/mySafeStaticDir” malicious = “/…/…/…/…/…/etc/passwd” os.path.join(t,malicious) ‘/…/…/…/…/…/etc/passwd’ ``` Since the “malicious” parameter represents an absolute path, the result of `os.path.join` ignores the static directory completely. Hence, untrusted input is passed via the `os.path.join` call to `flask.send_file` can lead to path traversal attacks.
In this case, the problems occurs due to the following code : https://github.com/onlaj/Piano-LED-Visualizer/blob/6a732caa812c83a807c711f3d091af99209cae7b/webinterface/views_api.py#L970
Here, the `value` parameter is attacker controlled. This parameter passes through the unsafe `os.path.join` call making the effective directory and filename passed to the `send_file` call attacker controlled. This leads to a path traversal attack.
Proof of Concept
The bug can be verified using a proof of concept similar to the one shown below.
``` curl --path-as-is ‘http://<domain>/api/change_setting?second_value=no_reload&disable_sequence=true&value=…/…/…/…/…/…/…/etc/passwd"’ ```
Remediation
This can be fixed by preventing flow of untrusted data to the vulnerable `send_file` function. In case the application logic necessiates this behaviour, one can either use the `flask.safe_join` to join untrusted paths or replace `flask.send_file` calls with `flask.send_from_directory` calls.
References
* [OWASP Path Traversal](https://owasp.org/www-community/attacks/Path_Traversal) * github/securitylab#669