CyberSecBulletin
CVE-2020-12641Exploited in the wildNVD status: Analyzed

Roundcube Webmail Remote Code Execution

CVE-2020-12641 is a critical-severity improper neutralization of special elements used in an OS command vulnerability in Webmail from Roundcube, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 1.2.10, 1.3.11, 1.4.4 as the first without the flaw, so updating Webmail to one of those releases or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on June 22, 2023, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update Webmail to 1.2.10 or 1.3.11 or 1.4.4, whichever matches your release line, or a later version.
  2. CISA's required action: Apply updates per vendor instructions.
  3. Read the advisory on roundcube.net for workarounds and exact fixed builds.
  4. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
RoundcubeWebmail1.2.0 up to, but not including, 1.2.10; 1.3.0 up to, but not including, 1.3.11; 1.4.0 up to, but not including, 1.4.41.2.10, 1.3.11, 1.4.4
openSUSEBackports Sle15.0Not stated
openSUSELeap15.1; 15.2Not stated

Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.19.8CriticalNVD
CVSS 3.19.8CriticalCISA (ADP)
CVSS 2.07.5HighNVD

Official description

rcube_image.php in Roundcube Webmail before 1.4.4 allows attackers to execute arbitrary code via shell metacharacters in a configuration setting for im_convert_path or im_identify_path.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Neutralization of Special Elements used in an OS Command

The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command before it is sent to a downstream component.

How developers prevent this class of flaw

  • If at all possible, use library calls rather than external processes to recreate the desired functionality.
  • For any data that will be used to generate a command to be executed, keep as much of that data out of external control as possible. For example, in web applications, this may require storing the data locally in the session's state instead of sending it out to the client in a hidden form field.
  • For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.

More Improper Neutralization of Special Elements used in an OS Command vulnerabilities (CWE-78)

Timeline

  1. CVE record published.
  2. Added to CISA's Known Exploited Vulnerabilities catalogue.
  3. Deadline for US federal agencies to remediate, set by CISA.
  4. CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: total).
  5. Record last changed materially (score, affected products, status or references).

References

Technical write-ups (may include proof of concept)

Other vulnerabilities in Webmail

All Webmail vulnerabilities

Recent Improper Neutralization of Special Elements used in an OS Command vulnerabilities

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