CyberSecBulletin
CVE-2022-4980NVD status: Deferred

Crypto Application Server (CAS): Missing Authentication for Critical Functionality

Published Updated By the CyberSecBulletin desk

CVE-2022-4980 is a critical-severity missing authentication for critical functionality vulnerability in Crypto Application Server (CAS) from General Bytes, with a CVSS 4.0 base score of 9.3 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 20220725.22, 20220531.38 as the first without the flaw, so updating Crypto Application Server (CAS) to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.66% chance of exploitation within 30 days, higher than 52% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Crypto Application Server (CAS) to 20220725.22 or 20220531.38, whichever matches your release line, or a later version.
  2. 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
General BytesCrypto Application Server (CAS)20201208 up to, but not including, 20220725.22; 20201208 up to, but not including, 20220531.3820220725.22, 20220531.38

Version data comes from the organisation that assigned the CVE. 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.
Attack requirements
NoneThe attack does not depend on a particular deployment or configuration.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Confidentiality (vulnerable system)
HighSerious loss of confidentiality on the vulnerable system.
Integrity (vulnerable system)
HighSerious loss of integrity on the vulnerable system.
Availability (vulnerable system)
LowLimited loss of availability on the vulnerable system.
Confidentiality (other systems)
NoneNo loss of confidentiality on systems beyond the vulnerable one.
Integrity (other systems)
NoneNo loss of integrity on systems beyond the vulnerable one.
Availability (other systems)
NoneNo loss of availability on systems beyond the vulnerable one.

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA (vulncheck.com).

Official description

General Bytes Crypto Application Server (CAS) beginning with version 20201208 prior to 20220531.38 (backport) and 20220725.22 (mainline) contains an authentication bypass in the admin web interface. An unauthenticated attacker could invoke the same URL used by the product's default-installation / first-admin creation page and create a new administrative account remotely. By gaining admin privileges, the attacker can change the ATM configuration resulting in redirected funds. Public vendor advisories and multiple independent writeups describe the vulnerability as a call to the page used for initial/default installation / first administration user creation; General Bytes has not publicly published the exact endpoint/parameter name. The issue was actively exploited in the wild against cloud-hosted and standalone CAS deployments (scanning exposed CAS instances on ports 7777/443), and publicly acknowledged by the General Bytes in September 2022.

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

The underlying weakness: Missing Authentication for Critical Functionality

The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

How developers prevent this class of flaw

  • 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.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using libraries with authentication capabilities such as OpenSSL or the ESAPI Authenticator.
  • When storing data in the cloud (e.g., S3 buckets, Azure blobs, Google Cloud Storage, etc.), use the provider's controls to require strong authentication for users who should be allowed to access the data.

More Missing Authentication for Critical Functionality vulnerabilities (CWE-306)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Missing Authentication for Critical Functionality vulnerabilities

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