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GeezerVison is showing github.com — [3.6] bpo-43285 Make ftplib not trust the PASV response. (GH-24838) (GH-24881) by miss-islington · Pull Request #24882 · python/cpython

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@miss-islington

@miss-islington miss-islington commented Mar 15, 2021 •
edited by bedevere-bot
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bpo-43285: Make ftplib not trust the PASV response.

The IPv4 address value returned from the server in response to the PASV command
should not be trusted. This prevents a malicious FTP server from using the
response to probe IPv4 address and port combinations on the client network.

Instead of using the returned address, we use the IP address we're
already connected to. This is the strategy other ftp clients adopted,
and matches the only strategy available for the modern IPv6 EPSV command
where the server response must return a port number and nothing else.

For the rare user who wants this ugly behavior, set a trust_server_pasv_ipv4_address
attribute on your ftplib.FTP instance to True..
(cherry picked from commit 0ab152c)

Co-authored-by: Gregory P. Smith [email protected]
(cherry picked from commit 664d1d1)

Co-authored-by: Gregory P. Smith [email protected]

https://bugs.python.org/issue43285

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@gpshead @miss-islington
[3.8] bpo-43285 Make ftplib not trust the PASV response. (pythonGH-24838
8759ca4 
) (pythonGH-24881)

bpo-43285: Make ftplib not trust the PASV response.

The IPv4 address value returned from the server in response to the PASV command
should not be trusted.  This prevents a malicious FTP server from using the
response to probe IPv4 address and port combinations on the client network.

Instead of using the returned address, we use the IP address we're
already connected to.  This is the strategy other ftp clients adopted,
and matches the only strategy available for the modern IPv6 EPSV command
where the server response must return a port number and nothing else.

For the rare user who _wants_ this ugly behavior, set a `trust_server_pasv_ipv4_address`
attribute on your `ftplib.FTP` instance to True..
(cherry picked from commit 0ab152c)

Co-authored-by: Gregory P. Smith <[email protected]>
(cherry picked from commit 664d1d1)

Co-authored-by: Gregory P. Smith <[email protected]>
@the-knights-who-say-ni the-knights-who-say-ni added the CLA signed label Mar 15, 2021
@bedevere-bot bedevere-bot mentioned this pull request Mar 15, 2021
[3.8] bpo-43285 Make ftplib not trust the PASV response. (GH-24838) #24881
Merged
@bedevere-bot bedevere-bot added type-bug An unexpected behavior, bug, or error type-security A security issue awaiting review labels Mar 15, 2021
@miss-islington

miss-islington commented Mar 15, 2021

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@gpshead: Status check is done, and it's a success ✅ .
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@gpshead gpshead changed the title [3.6] [3.8] bpo-43285 Make ftplib not trust the PASV response. (GH-24838) (GH-24881) [3.6] bpo-43285 Make ftplib not trust the PASV response. (GH-24838) (GH-24881) Mar 15, 2021
@gpshead gpshead assigned ned-deily Mar 15, 2021
@miss-islington

miss-islington commented Mar 15, 2021

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@gpshead: Status check is done, and it's a failure ❌ .
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gpshead added 2 commits March 16, 2021 04:31
@gpshead
Add a What's New entry for 3.6.14.
668d22e
@gpshead
typo
9678422
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Added a what's new entry.
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@ned-deily
fix underline
e5fb26d
@ned-deily
ned-deily merged commit 4134f15 into python:3.6 Mar 16, 2021
@bedevere-bot bedevere-bot removed the awaiting review label Mar 16, 2021
@miss-islington
miss-islington deleted the backport-664d1d1-3.6 branch March 16, 2021 21:08
gentoo-bot pushed a commit to gentoo/cpython that referenced this pull request Apr 3, 2021
@miss-islington @mgorny
[3.6] bpo-43285 Make ftplib not trust the PASV response. (pythonGH-24838
fe31479 
) (pythonGH-24881) (pythonGH-24882)

The IPv4 address value returned from the server in response to the PASV command
should not be trusted.  This prevents a malicious FTP server from using the
response to probe IPv4 address and port combinations on the client network.

Instead of using the returned address, we use the IP address we're
already connected to.  This is the strategy other ftp clients adopted,
and matches the only strategy available for the modern IPv6 EPSV command
where the server response must return a port number and nothing else.

For the rare user who _wants_ this ugly behavior, set a `trust_server_pasv_ipv4_address`
attribute on your `ftplib.FTP` instance to True..
(cherry picked from commit 0ab152c)

Co-authored-by: Gregory P. Smith <[email protected]>
(cherry picked from commit 664d1d1)

Rebased for Python 2.7 by Michał Górny <[email protected]>
rickprice added a commit to ActiveState/cpython that referenced this pull request Feb 8, 2024
@rickprice @gpshead
CVE-2021-4180 cherry-pick Fix 4134f15
b903a48 
[3.6] bpo-43285 Make ftplib not trust the PASV response. (pythonGH-24838) (G…

…H-24881) (pythonGH-24882)

The IPv4 address value returned from the server in response to the PASV command
should not be trusted.  This prevents a malicious FTP server from using the
response to probe IPv4 address and port combinations on the client network.

Instead of using the returned address, we use the IP address we're
already connected to.  This is the strategy other ftp clients adopted,
and matches the only strategy available for the modern IPv6 EPSV command
where the server response must return a port number and nothing else.

For the rare user who _wants_ this ugly behavior, set a `trust_server_pasv_ipv4_address`
attribute on your `ftplib.FTP` instance to True..
(cherry picked from commit 0ab152c)

Co-authored-by: Gregory P. Smith <[email protected]>
(cherry picked from commit 664d1d1)
rickprice added a commit to ActiveState/cpython that referenced this pull request Feb 8, 2024
@rickprice @gpshead
CVE-2021-4180 cherry-pick Fix 4134f15
36a17ec 
[3.6] bpo-43285 Make ftplib not trust the PASV response. (pythonGH-24838) (G…

…H-24881) (pythonGH-24882)

The IPv4 address value returned from the server in response to the PASV command
should not be trusted.  This prevents a malicious FTP server from using the
response to probe IPv4 address and port combinations on the client network.

Instead of using the returned address, we use the IP address we're
already connected to.  This is the strategy other ftp clients adopted,
and matches the only strategy available for the modern IPv6 EPSV command
where the server response must return a port number and nothing else.

For the rare user who _wants_ this ugly behavior, set a `trust_server_pasv_ipv4_address`
attribute on your `ftplib.FTP` instance to True..
(cherry picked from commit 0ab152c)

Co-authored-by: Gregory P. Smith <[email protected]>
(cherry picked from commit 664d1d1)
rickprice added a commit to ActiveState/cpython that referenced this pull request Feb 13, 2024
@rickprice @gpshead
CVE-2021-4180 cherry-pick Fix 4134f15
235a201 
[3.6] bpo-43285 Make ftplib not trust the PASV response. (pythonGH-24838) (G…

…H-24881) (pythonGH-24882)

The IPv4 address value returned from the server in response to the PASV command
should not be trusted.  This prevents a malicious FTP server from using the
response to probe IPv4 address and port combinations on the client network.

Instead of using the returned address, we use the IP address we're
already connected to.  This is the strategy other ftp clients adopted,
and matches the only strategy available for the modern IPv6 EPSV command
where the server response must return a port number and nothing else.

For the rare user who _wants_ this ugly behavior, set a `trust_server_pasv_ipv4_address`
attribute on your `ftplib.FTP` instance to True..
(cherry picked from commit 0ab152c)

Co-authored-by: Gregory P. Smith <[email protected]>
(cherry picked from commit 664d1d1)
rickprice added a commit to ActiveState/cpython that referenced this pull request Feb 13, 2024
@rickprice @gpshead
CVE-2021-4189 cherry-pick Fix 4134f15
73bb207 
[3.6] bpo-43285 Make ftplib not trust the PASV response. (pythonGH-24838) (G…

…H-24881) (pythonGH-24882)

The IPv4 address value returned from the server in response to the PASV command
should not be trusted.  This prevents a malicious FTP server from using the
response to probe IPv4 address and port combinations on the client network.

Instead of using the returned address, we use the IP address we're
already connected to.  This is the strategy other ftp clients adopted,
and matches the only strategy available for the modern IPv6 EPSV command
where the server response must return a port number and nothing else.

For the rare user who _wants_ this ugly behavior, set a `trust_server_pasv_ipv4_address`
attribute on your `ftplib.FTP` instance to True..
(cherry picked from commit 0ab152c)

Co-authored-by: Gregory P. Smith <[email protected]>
(cherry picked from commit 664d1d1)
rickprice added a commit to ActiveState/cpython that referenced this pull request Jun 26, 2024
@rickprice @gpshead
CVE-2021-4189 cherry-pick Fix 4134f15
d72594e 
[3.6] bpo-43285 Make ftplib not trust the PASV response. (pythonGH-24838) (G…

…H-24881) (pythonGH-24882)

The IPv4 address value returned from the server in response to the PASV command
should not be trusted.  This prevents a malicious FTP server from using the
response to probe IPv4 address and port combinations on the client network.

Instead of using the returned address, we use the IP address we're
already connected to.  This is the strategy other ftp clients adopted,
and matches the only strategy available for the modern IPv6 EPSV command
where the server response must return a port number and nothing else.

For the rare user who _wants_ this ugly behavior, set a `trust_server_pasv_ipv4_address`
attribute on your `ftplib.FTP` instance to True..
(cherry picked from commit 0ab152c)

Co-authored-by: Gregory P. Smith <[email protected]>
(cherry picked from commit 664d1d1)
icanhasmath pushed a commit to ActiveState/cpython that referenced this pull request Jul 30, 2024
@rickprice @gpshead @icanhasmath
CVE-2021-4189 cherry-pick Fix 4134f15
8ebb54f 
[3.6] bpo-43285 Make ftplib not trust the PASV response. (pythonGH-24838) (G…

…H-24881) (pythonGH-24882)

The IPv4 address value returned from the server in response to the PASV command
should not be trusted.  This prevents a malicious FTP server from using the
response to probe IPv4 address and port combinations on the client network.

Instead of using the returned address, we use the IP address we're
already connected to.  This is the strategy other ftp clients adopted,
and matches the only strategy available for the modern IPv6 EPSV command
where the server response must return a port number and nothing else.

For the rare user who _wants_ this ugly behavior, set a `trust_server_pasv_ipv4_address`
attribute on your `ftplib.FTP` instance to True..
(cherry picked from commit 0ab152c)

Co-authored-by: Gregory P. Smith <[email protected]>
(cherry picked from commit 664d1d1)
icanhasmath pushed a commit to ActiveState/cpython that referenced this pull request Jul 30, 2024
@rickprice @gpshead @icanhasmath
CVE-2021-4189 cherry-pick Fix 4134f15
1a25963 
[3.6] bpo-43285 Make ftplib not trust the PASV response. (pythonGH-24838) (G…

…H-24881) (pythonGH-24882)

The IPv4 address value returned from the server in response to the PASV command
should not be trusted.  This prevents a malicious FTP server from using the
response to probe IPv4 address and port combinations on the client network.

Instead of using the returned address, we use the IP address we're
already connected to.  This is the strategy other ftp clients adopted,
and matches the only strategy available for the modern IPv6 EPSV command
where the server response must return a port number and nothing else.

For the rare user who _wants_ this ugly behavior, set a `trust_server_pasv_ipv4_address`
attribute on your `ftplib.FTP` instance to True..
(cherry picked from commit 0ab152c)

Co-authored-by: Gregory P. Smith <[email protected]>
(cherry picked from commit 664d1d1)
@ricexdream ricexdream mannequin mentioned this pull request May 10, 2026
ftplib should not use the host from the PASV response #87451
Closed
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