Arch Linux Security Advisory ASA-202106-7

Severity: High
Date : 2021-06-01
CVE-ID : CVE-2021-22898 CVE-2021-22901
Package : lib32-libcurl-compat
Type : multiple issues
Remote : Yes
Link : https://security.archlinux.org/AVG-1998

Summary

The package lib32-libcurl-compat before version 7.77.0-1 is vulnerable
to multiple issues including arbitrary code execution and information
disclosure.

Resolution

Upgrade to 7.77.0-1.

pacman -Syu “lib32-libcurl-compat>=7.77.0-1”

The problems have been fixed upstream in version 7.77.0.

Workaround

• CVE-2021-22898 can be mitigated by avoiding to use the -t command
  line option and CURLOPT_TELNETOPTIONS.
• No known workaround exists for CVE-2021-22901.

Description

• CVE-2021-22898 (information disclosure)

A security issue has been found in curl before version 7.77.0. curl
supports the -t command line option, known as CURLOPT_TELNETOPTIONS in
libcurl. This rarely used option is used to send variable=content pairs
to TELNET servers. Due to flaw in the option parser for sending NEW_ENV
variables, libcurl could be made to pass on uninitialized data from a
stack based buffer to the server. Therefore potentially revealing
sensitive internal information to the server using a clear-text network
protocol.

• CVE-2021-22901 (arbitrary code execution)

libcurl before version 7.77.0 can be tricked into using already freed
memory when a new TLS session is negotiated or a client certificate is
requested on an existing connection. For example, this can happen when
a TLS server requests a client certificate on a connection that was
established without one. A malicious server can use this in rare
unfortunate circumstances to potentially reach remote code execution in
the client. The flaw can only happen in libcurl built to use OpenSSL.

Impact

curl could disclose potentially sensitive memory information to a
remote server over Telnet when an uncommon option is used.
Additionally, a remote attacker could cause arbitrary code execution
through a crafted TLS handshake.

References

https://curl.se/docs/CVE-2021-22898.html
https://github.com/curl/curl/commit/39ce47f219b09c380b81f89fe54ac586c8db6bde
https://curl.se/docs/CVE-2021-22901.html
https://github.com/curl/curl/commit/7f4a9a9b2a49547eae24d2e19bc5c346e9026479
https://security.archlinux.org/CVE-2021-22898
https://security.archlinux.org/CVE-2021-22901