Papercut Remote Code Execution Scanner

Papercut is a print management system widely used across educational and corporate environments. Its primary function is to manage and control printing resources, ensuring efficient and effective use of printing services. Schools and universities often use Papercut to monitor student printing activity and manage costs. In business environments, it helps in tracking employee printing for cost control and security purposes. The software integrates with most types of printers and works autonomously to regulate printing jobs. Due to its extensive use, vulnerabilities in Papercut can have widespread implications.

The vulnerability in question is a Remote Code Execution (RCE) that is facilitated by the Log4j JNDI lookup mechanism, widely known as Log4Shell. This flaw allows attackers to execute arbitrary code on a target server. The RCE vulnerability requires minimal interaction and takes advantage of system privileges, posing a significant threat to system integrity. When successfully exploited, this vulnerability can lead to unauthorized access and control over affected systems.

In technical terms, the vulnerability is leveraged through crafted JNDI lookups. The key vulnerable endpoint involves the improper handling of untrusted data via Log4j, specifically using JNDI references. The combination of LDAP protocol in JNDI lookups and Papercut's configuration creates an exploit path for attackers. Key parameters like the inputUsername in HTTP requests become vectors for these malicious JNDI entries. The attack predominantly requires creating a crafted HTTP request which triggers the DNS interaction used in detecting the vulnerability.

The possible effects of exploiting this RCE vulnerability in Papercut can be severe. Once an attacker gains remote control, they can deploy malware, exfiltrate data, or even pivot to other segments of the network to inflict greater harm. The integrity and confidentiality of information managed by Papercut are at risk, as administrative access could be compromised. Additionally, the attackers may disrupt the entire printing infrastructure, leading to operational chaos in environments relying heavily on print management. Such breaches could also result in financial losses and reputational damage for organizations.

REFERENCES

• https://www.papercut.com/kb/Main/Log4Shell-CVE-2021-44228#product-status