Difference between revisions of "Scp"

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[[wikipedia:Secure copy]] (<code>scp</code>) is a means of securely transferring computer files between a local host and a remote host or between two remote hosts. scp implements a [[progress]] bar to estimate transfers.
 
[[wikipedia:Secure copy]] (<code>scp</code>) is a means of securely transferring computer files between a local host and a remote host or between two remote hosts. scp implements a [[progress]] bar to estimate transfers.
  
 
http://man7.org/linux/man-pages/man1/scp.1.html
 
http://man7.org/linux/man-pages/man1/scp.1.html
  
== Example ==
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scp help
  scp USERNAME@SERVER:/tmp/FILE ./
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usage: scp [-346ABCpqrTv] [-c cipher] [-F ssh_config] [-i identity_file]
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            [-J destination] [-l limit] [-o ssh_option] [-P port]
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            [-S program] source ... target
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== Examples ==
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  scp your_username@your_server:/tmp/FILE ./
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scp -r your_username@your_server:/path/to/your/remote/folder ./
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scp -r [[-P]] 1234 your_username@your_server:/path/to/your/remote/folder ./
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scp your_username@your_server:/tmp/FILE ./
 
  USERNAME@SERVER's password:
 
  USERNAME@SERVER's password:
 
  Could not chdir to home directory /home/USERNAME: No such file or directory
 
  Could not chdir to home directory /home/USERNAME: No such file or directory
 
  protocol error: mtime.sec not present
 
  protocol error: mtime.sec not present
  
  scp -r .../...
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  scp USERNAME@SERVER:/tmp/your_folder ./
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scp: /tmp/your_folder: not a regular file
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[[scp -r]] USERNAME@SERVER:/tmp/your_folder ./
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scp: /tmp/your_folder/your_file: Permission denied
  
 
== Security ==
 
== Security ==
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* Review security advisories related to <code>scp</code>: [[CVE]]-2019-6111<ref>https://nvd.nist.gov/vuln/detail/CVE-2019-6111</ref> related to <code>[[scp]]</code> tool and protocol allowing to overwrite arbitrary files in the scp client target directory
 
* Review security advisories related to <code>scp</code>: [[CVE]]-2019-6111<ref>https://nvd.nist.gov/vuln/detail/CVE-2019-6111</ref> related to <code>[[scp]]</code> tool and protocol allowing to overwrite arbitrary files in the scp client target directory
 
* <code>[[pv]] </dev/zero | ssh REMOTE_SERVER 'cat >/dev/null'</code>
 
* <code>[[pv]] </dev/zero | ssh REMOTE_SERVER 'cat >/dev/null'</code>
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== News ==
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* [[OpenSSH 9.0]] Aug 2022 https://www.openssh.com/txt/release-9.0 switches scp from using the legacy scp/rcp protocol to using the SFTP protocol by default
  
 
== Related terms ==
 
== Related terms ==
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* <code>[[scp -3]]</code>  
 
* <code>[[scp -3]]</code>  
 
* [[Resume transmissions]]: <code>[[rsync]] -P or --partial --progress</code>
 
* [[Resume transmissions]]: <code>[[rsync]] -P or --partial --progress</code>
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* [[uses: actions/upload-artifact]] in [[GitHub Actions]]
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* [[GitLab CI: artifacts:]]
  
 
== See also ==
 
== See also ==

Latest revision as of 16:19, 31 October 2023

wikipedia:Secure copy (scp) is a means of securely transferring computer files between a local host and a remote host or between two remote hosts. scp implements a progress bar to estimate transfers.

http://man7.org/linux/man-pages/man1/scp.1.html

scp help
usage: scp [-346ABCpqrTv] [-c cipher] [-F ssh_config] [-i identity_file]
            [-J destination] [-l limit] [-o ssh_option] [-P port]
            [-S program] source ... target

Examples[edit]

scp your_username@your_server:/tmp/FILE ./
scp -r your_username@your_server:/path/to/your/remote/folder ./
scp -r -P 1234 your_username@your_server:/path/to/your/remote/folder ./
scp your_username@your_server:/tmp/FILE ./
USERNAME@SERVER's password:
Could not chdir to home directory /home/USERNAME: No such file or directory
protocol error: mtime.sec not present
scp USERNAME@SERVER:/tmp/your_folder ./
scp: /tmp/your_folder: not a regular file
scp -r USERNAME@SERVER:/tmp/your_folder ./
scp: /tmp/your_folder/your_file: Permission denied

Security[edit]

According to OpenSSH developers in April 2019 the scp protocol is outdated, inflexible and not readily fixed; they recommend the use of more modern protocols like sftp and rsync for file transfer.[1]

OpenSSH 8.3 May 2020 scp(1): when receiving files, scp(1) could be become desynchronised if a utimes (2) system call failed. This could allow file contents to be interpreted as file metadata and thereby permit an adversary to craft a file system that, when copied with scp(1) in a configuration that caused utimes(2) to fail (e.g. under a SELinux policy or syscall sandbox), transferred different file names and contents to the actual file system layout. Exploitation of this is not likely as utimes(2) does not fail under normal circumstances. Successful exploitation is not silent - the output of scp(1) would show transfer errors followed by the actual file(s) that were received. Finally, filenames returned from the peer are (since openssh-8.0) matched against the user's requested destination, thereby disallowing a successful exploit from writing files outside the user's selected target glob (or directory, in the case of a recursive transfer). This ensures that this attack can achieve no more than a hostile peer is already able to achieve within the scp protocol.

Activities[edit]

News[edit]

Related terms[edit]

See also[edit]

  • "OpenSSH 8.0". OpenSSH Release Notes. 17 April 2019.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  • https://nvd.nist.gov/vuln/detail/CVE-2019-6111
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