CVE-2020-20277: There are multiple unauthenticated directory traversal vulnerabilities in different FTP commands in uftpd FTP server versions 2.7 to 2.10 due to improper…

PriorityP275critical9.8CVSS 3.1

AVNACLPRNUINSUCHIHAH

EXPLOIT

EPSS

25.25%

97.7th percentile

There are multiple unauthenticated directory traversal vulnerabilities in different FTP commands in uftpd FTP server versions 2.7 to 2.10 due to improper implementation of a chroot jail in common.c's compose_abspath function that can be abused to read or write to arbitrary files on the filesystem, leak process memory, or potentially lead to remote code execution.

Affected

1 ranges

Vendor	Product	Version range	Fixed in
troglobit	uftpd	2.7 – 2.10	—

Detection & IOCsextracted from sources · hover to see the quote

commandls ../../../↗

commandRETR ../../../etc/passwd↗

path../../../etc/passwd↗

→Monitor FTP command streams for directory traversal sequences (e.g., '../') in FTP commands such as LIST/LS, RETR, STOR, and CWD targeting uftpd versions 2.7–2.10. ↗
→Alert on FTP RETR or LIST commands containing '../' path components, particularly sequences traversing three or more levels (e.g., '../../../'), which indicate chroot escape attempts against uftpd. ↗
→Flag anonymous FTP login sessions on uftpd servers followed by directory traversal commands, as anonymous login enables unauthenticated arbitrary file read. ↗
→Detect abuse of the FTP PORT command with loopback or unexpected IP addresses (e.g., 127,0,0,1) in combination with traversal-based RETR commands, indicating active exploitation. ↗

·The directory traversal is exploitable without authentication if the uftpd server has anonymous login enabled; restrict anonymous FTP access to reduce attack surface. ↗
·Arbitrary file read via traversal is only possible when uftpd is NOT running as root; running as root may limit read impact but does not eliminate the vulnerability or RCE risk. ↗
·The vulnerability resides in the compose_abspath function in common.c and affects all uftpd versions 2.7 through 2.10; all FTP commands processed through this function are potentially affected. ↗

CVSS provenance

nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvdv2.07.5HIGHAV:N/AC:L/Au:N/C:P/I:P/A:P

osv7.5HIGH

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