Amazon Linux 2 : curl (ALAS-2021-1724)
critical Nessus Plugin ID 155980
Language:
Synopsis
The remote Amazon Linux 2 host is missing a security update.Description
The version of curl installed on the remote host is prior to 7.79.1-1. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2021-1724 advisory.- When sending data to an MQTT server, libcurl <= 7.73.0 and 7.78.0 could in some circumstances erroneously keep a pointer to an already freed memory area and both use that again in a subsequent call to send data and also free it *again*. (CVE-2021-22945)
- 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 or`CURLOPT_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. (CVE-2021-22946)
- When curl >= 7.20.0 and <= 7.78.0 connects to an IMAP or POP3 server to retrieve data using STARTTLS to upgrade to TLS security, the server can respond and send back multiple responses at once that curl caches.
curl would then upgrade to TLS but not flush the in-queue of cached responses but instead continue using and trustingthe responses it got *before* the TLS handshake as if they were authenticated.Using this flaw, it allows a Man-In-The-Middle attacker to first inject the fake responses, then pass-through the TLS traffic from the legitimate server and trick curl into sending data back to the user thinking the attacker's injected data comes from the TLS-protected server. (CVE-2021-22947)
Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.
Solution
Run 'yum update curl' to update your system.See Also
https://alas.aws.amazon.com/AL2/ALAS-2021-1724.html
https://access.redhat.com/security/cve/CVE-2021-22945
Plugin Details
Severity: Critical
ID: 155980
File Name: al2_ALAS-2021-1724.nasl
Version: 1.2
Type: local
Agent: unix
Published: 12/10/2021
Updated: 12/10/2021
Supported Sensors: Frictionless Assessment Agent, Frictionless Assessment AWS, Nessus Agent
Risk Information
CVSS Score Source: CVE-2021-22945
VPR
Risk Factor: Medium
Score: 5.2
CVSS v2
Risk Factor: Medium
Base Score: 5.8
Temporal Score: 4.3
Vector: AV:N/AC:M/Au:N/C:P/I:N/A:P
Temporal Vector: E:U/RL:OF/RC:C
CVSS v3
Risk Factor: Critical
Base Score: 9.1
Temporal Score: 7.9
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Temporal Vector: E:U/RL:O/RC:C
Vulnerability Information
CPE: p-cpe:/a:amazon:linux:curl, p-cpe:/a:amazon:linux:curl-debuginfo, p-cpe:/a:amazon:linux:libcurl, p-cpe:/a:amazon:linux:libcurl-devel, cpe:/o:amazon:linux:2
Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list
Exploit Ease: No known exploits are available
Patch Publication Date: 12/8/2021
Vulnerability Publication Date: 9/17/2021
Reference Information
CVE: CVE-2021-22945, CVE-2021-22946, CVE-2021-22947
ALAS: 2021-1724