CVE-2023-3603

Summary

A missing allocation check in sftp server processing read requests may cause a NULL dereference on low-memory conditions. The malicious client can request up to 4GB SFTP reads, causing allocation of up to 4GB buffers, which was not being checked for failure. This will likely crash the authenticated user's sftp server connection (if implemented as forking as recommended). For thread-based servers, this might also cause DoS for legitimate users.

Given this code is not in any released versions, no security releases have been issued.

Affected Software

Weaknesses

• CWE-476: NULL Pointer Dereference

Workarounds

The SFTP server implementation is based on callbacks so you can rewrite the sftp_channel_default_data_callback() to provide additional checks.

[1] https://gitlab.com/libssh/libssh-mirror/-/blob/master/examples/sample_sftpserver.c#L330

ADP Enrichment

CVE Program Container

Additional References

• https://access.redhat.com/security/cve/CVE-2023-3603
• https://bugzilla.redhat.com/show_bug.cgi?id=2221791

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: no
  • Technical Impact: partial

References

• https://access.redhat.com/security/cve/CVE-2023-3603
• https://bugzilla.redhat.com/show_bug.cgi?id=2221791

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