CVE-2010-0542 in CUPS
Summary
by MITRE
The _WriteProlog function in texttops.c in texttops in the Text Filter subsystem in CUPS before 1.4.4 does not check the return values of certain calloc calls, which allows remote attackers to cause a denial of service (NULL pointer dereference or heap memory corruption) or possibly execute arbitrary code via a crafted file.
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Analysis
by VulDB Data Team • 12/08/2024
The vulnerability described in CVE-2010-0542 resides within the CUPS (Common Unix Printing System) printing stack, specifically in the Text Filter subsystem's texttops.c component. This issue affects CUPS versions prior to 1.4.4 and represents a critical memory management flaw that could be exploited remotely. The vulnerability stems from improper error handling in the _WriteProlog function where certain calloc memory allocation calls lack proper return value validation. This fundamental flaw creates a pathway for malicious actors to manipulate the printing process and potentially gain unauthorized system access.
The technical implementation of this vulnerability involves the calloc function which allocates memory and initializes it to zero, returning a pointer to the allocated memory block. When these allocation calls fail, they return NULL pointers which should be checked before proceeding with operations. However, the _WriteProlog function in texttops.c fails to validate these return values, creating a scenario where subsequent code operations attempt to use NULL pointers or operate on uninitialized memory regions. This oversight can lead to either NULL pointer dereference exceptions that crash the printing daemon or heap memory corruption that may allow for arbitrary code execution through carefully crafted input files.
From an operational perspective, this vulnerability presents significant risks to networked printing environments where CUPS serves as the primary printing system. Attackers can exploit this weakness by submitting specially crafted print jobs that trigger the flawed memory allocation path, resulting in either denial of service conditions that prevent legitimate printing operations or more severe outcomes where code execution occurs. The remote nature of this attack means that any system running vulnerable CUPS versions and accepting print jobs from untrusted sources becomes a potential target. This vulnerability particularly impacts enterprise environments where centralized print servers are common, as a successful exploitation could compromise entire print infrastructure or potentially provide a foothold for further attacks.
The vulnerability aligns with CWE-754 in the Common Weakness Enumeration catalog, which classifies improper check for null pointer dereference as a weakness that can lead to system instability and potential code execution. Additionally, this issue maps to several ATT&CK tactics including privilege escalation and execution through the use of compromised print services as attack vectors. Organizations should prioritize patching this vulnerability immediately, as it represents a well-known and exploitable flaw that could be leveraged by threat actors without requiring significant technical expertise. The recommended mitigation strategy involves upgrading to CUPS version 1.4.4 or later, where proper error handling has been implemented to validate calloc return values and prevent the exploitation of this memory management flaw.
This vulnerability demonstrates the critical importance of proper error handling in system components that process external input, particularly in server applications that handle untrusted data. The lack of basic input validation and error checking in memory allocation operations creates a dangerous precedent for system stability and security. Organizations should implement comprehensive monitoring for suspicious print job patterns and maintain updated security patches across all printing infrastructure components to prevent exploitation of similar vulnerabilities that may exist in other subsystems of the CUPS architecture or related printing services.