cbcvebase.
CVE-2019-6111
published 2019-01-31

CVE-2019-6111: 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…

PriorityP185medium5.9CVSS 3.1
AVNACHPRNUINSUCNIHAN
ITWEXPLOITVulnCheck KEVRansomware
Exploited in the wild
EPSS
58.20%
99.0th percentile
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).

Affected

57 ranges· showing 25
VendorProductVersion rangeFixed in
apachemina_sshd
canonicalubuntu_linux
canonicalubuntu_linux
canonicalubuntu_linux
canonicalubuntu_linux
debiandebian_linux
debiandebian_linux
debianlibssh< libssh 0.12.0-1 (forky)libssh 0.12.0-1 (forky)
debiannetkit-rsh< netkit-rsh 0.17-20 (bookworm)netkit-rsh 0.17-20 (bookworm)
debianopenssh< openssh 1:7.9p1-9 (bookworm)openssh 1:7.9p1-9 (bookworm)
fedoraprojectfedora
freebsdfreebsd< 12.012.0
freebsdfreebsd
fujitsum10-1_firmware< xcp2361xcp2361
fujitsum10-1_firmware< xcp3070xcp3070
fujitsum10-4_firmware< xcp2361xcp2361
fujitsum10-4_firmware< xcp3070xcp3070
fujitsum10-4s_firmware< xcp2361xcp2361
fujitsum10-4s_firmware< xcp3070xcp3070
fujitsum12-1_firmware< xcp2361xcp2361
fujitsum12-1_firmware< xcp3070xcp3070
fujitsum12-2_firmware< xcp2361xcp2361
fujitsum12-2_firmware< xcp3070xcp3070
fujitsum12-2s_firmware< xcp2361xcp2361
fujitsum12-2s_firmware< xcp3070xcp3070

Detection & IOCsextracted from sources · hover to see the quote

port2222
filenameexploit.txt
commandC0664 {} exploit.txt\n
path.ssh/authorized_keys
bytes
\x1b[1A
  • Detect ANSI escape sequences (specifically ESC[1A / \x1b[1A) sent over SCP stderr channel, which are used to hide the transfer of additional malicious files from the client's progress display.
  • Monitor SCP sessions where the server sends multiple 'C' (copy) protocol messages for a single-file download request — the extra file transfer is the exploit payload delivery mechanism for CVE-2019-6111.
  • Alert on SCP recursive (-r) operations to/from untrusted servers, especially where subdirectory manipulation could result in writes to sensitive paths like .ssh/authorized_keys.
  • ·The exploit PoC server accepts any username and password (no authentication enforcement), meaning the rogue server is trivially accessible to any connecting SCP client — defenders should not rely on authentication as a mitigation signal.
  • ·The initial patch for CVE-2019-6111 in USN-3885-1 was incomplete and required a follow-up fix in USN-3885-2; deployments that only applied the first patch may still be vulnerable.
  • ·The vulnerability affects PAN-OS versions before 7.1.26, 8.1.13, and 9.0.7; PAN-OS 8.0 reached end-of-life on October 31, 2019 and is no longer covered by security assurance policies.

CVSS provenance

nvdv3.15.9MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
nvdv2.05.8MEDIUMAV:N/AC:M/Au:N/C:N/I:P/A:P
osv5.9MEDIUM
vulncheck5.9MEDIUM
vendor_debian5.9MEDIUM
vendor_redhat5.9MEDIUM
vendor_ubuntu5.9MEDIUM
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