An issue was discovered in OpenSSH 7.9. Due to the...

Vulnerability Description

An issue was discovered in OpenSSH 7.9. Due to the scp implementation being derived from 1983 rcp, the server chooses which files/directories are sent to the client. However, the scp client only performs cursory validation of the object name returned (only directory traversal attacks are prevented). A malicious scp server (or Man-in-The-Middle attacker) can overwrite arbitrary files in the scp client target directory. If recursive operation (-r) is performed, the server can manipulate subdirectories as well (for example, to overwrite the .ssh/authorized_keys file).

References

• https://www.debian.org/security/2019/dsa-4387
• https://security.netapp.com/advisory/ntap-20190213-0001/
• http://www.securityfocus.com/bid/106741
• https://cvsweb.openbsd.org/src/usr.bin/ssh/scp.c
• https://usn.ubuntu.com/3885-1/
• https://usn.ubuntu.com/3885-2/
• https://bugzilla.redhat.com/show_bug.cgi?id=1677794
• https://sintonen.fi/advisories/scp-client-multiple-vulnerabilities.txt
• https://www.exploit-db.com/exploits/46193/
• https://security.gentoo.org/glsa/201903-16
• https://lists.debian.org/debian-lts-announce/2019/03/msg00030.html
• http://www.openwall.com/lists/oss-security/2019/04/18/1
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/W3YVQ2BPTOVDCFDVNC2GGF5P5ISFG37G/
• https://lists.apache.org/thread.html/c45d9bc90700354b58fb7455962873c44229841880dcb64842fa7d23%40%3Cdev.mina.apache.org%3E
• https://lists.apache.org/thread.html/c7301cab36a86825359e1b725fc40304d1df56dc6d107c1fe885148b%40%3Cdev.mina.apache.org%3E
• https://lists.apache.org/thread.html/e47597433b351d6e01a5d68d610b4ba195743def9730e49561e8cf3f%40%3Cdev.mina.apache.org%3E
• http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00058.html
• https://www.freebsd.org/security/advisories/FreeBSD-EN-19:10.scp.asc
• https://lists.apache.org/thread.html/d540139359de999b0f1c87d05b715be4d7d4bec771e1ae55153c5c7a%40%3Cdev.mina.apache.org%3E
• https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html
• https://access.redhat.com/errata/RHSA-2019:3702
• http://www.openwall.com/lists/oss-security/2022/08/02/1
• https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf