CVE Vulnerabilities

CVE-2021-22946

Cleartext Transmission of Sensitive Information

Published: Sep 29, 2021 | Modified: Mar 27, 2024
CVSS 3.x
7.5
HIGH
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS 2.x
5 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:N
RedHat/V2
RedHat/V3
7.5 MODERATE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Ubuntu
MEDIUM

A user can tell curl >= 7.20.0 and <= 7.78.0 to require a successful upgrade to TLS when speaking to an IMAP, POP3 or FTP server (--ssl-reqd on the command line orCURLOPT_USE_SSL set to CURLUSESSL_CONTROL or CURLUSESSL_ALL withlibcurl). This requirement could be bypassed if the server would return a properly crafted but perfectly legitimate response.This flaw would then make curl silently continue its operations withoutTLS contrary to the instructions and expectations, exposing possibly sensitive data in clear text over the network.

Weakness

The product transmits sensitive or security-critical data in cleartext in a communication channel that can be sniffed by unauthorized actors.

Affected Software

Name Vendor Start Version End Version
Curl Haxx 7.20.0 (including) 7.79.0 (excluding)
Curl Ubuntu bionic *
Curl Ubuntu devel *
Curl Ubuntu esm-infra/xenial *
Curl Ubuntu focal *
Curl Ubuntu hirsute *
Curl Ubuntu impish *
Curl Ubuntu jammy *
Curl Ubuntu trusty *
Curl Ubuntu trusty/esm *
Curl Ubuntu xenial *
.NET Core on Red Hat Enterprise Linux RedHat rh-dotnet31-curl-0:7.61.1-22.el7_9 *
Red Hat Enterprise Linux 8 RedHat curl-0:7.61.1-18.el8_4.2 *
Red Hat Enterprise Linux 8.2 Extended Update Support RedHat curl-0:7.61.1-12.el8_2.4 *

Extended Description

Many communication channels can be “sniffed” (monitored) by adversaries during data transmission. For example, in networking, packets can traverse many intermediary nodes from the source to the destination, whether across the internet, an internal network, the cloud, etc. Some actors might have privileged access to a network interface or any link along the channel, such as a router, but they might not be authorized to collect the underlying data. As a result, network traffic could be sniffed by adversaries, spilling security-critical data. Applicable communication channels are not limited to software products. Applicable channels include hardware-specific technologies such as internal hardware networks and external debug channels, supporting remote JTAG debugging. When mitigations are not applied to combat adversaries within the product’s threat model, this weakness significantly lowers the difficulty of exploitation by such adversaries. When full communications are recorded or logged, such as with a packet dump, an adversary could attempt to obtain the dump long after the transmission has occurred and try to “sniff” the cleartext from the recorded communications in the dump itself.

Potential Mitigations

References