CVE-2004-1007 in bogofilter
Summary
by MITRE
The quoted-printable decoder in bogofilter 0.17.4 to 0.92.7 allows remote attackers to cause a denial of service (application crash) via mail headers that cause a line feed (LF) to be replaced by a null byte that is written to an incorrect memory address.
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Analysis
by VulDB Data Team • 07/01/2021
The vulnerability identified as CVE-2004-1007 represents a critical denial of service flaw within the quoted-printable decoding functionality of bogofilter versions ranging from 0.17.4 through 0.92.7. This issue stems from improper handling of email headers containing quoted-printable encoded content, specifically when processing line feed characters that are subsequently converted to null bytes during the decoding process. The flaw manifests when the application encounters malformed mail headers that trigger an incorrect memory write operation, leading to application instability and potential system crashes.
The technical implementation of this vulnerability involves the quoted-printable decoder's failure to properly validate input boundaries when processing encoded content. When the decoder encounters a line feed character within quoted-printable encoded headers, it performs a transformation that replaces the line feed with a null byte. However, the subsequent memory management logic fails to account for this transformation properly, resulting in writes to memory addresses that are either invalid or outside the intended buffer boundaries. This memory corruption directly violates fundamental software security principles and can be exploited by remote attackers to disrupt service availability.
From an operational perspective, this vulnerability presents a significant risk to email filtering systems that rely on bogofilter for spam detection and prevention. Attackers can craft malicious email headers that, when processed by the vulnerable software, will trigger the application crash, effectively rendering the email filtering service unavailable. The impact extends beyond simple service disruption as this flaw can be leveraged in broader denial of service attacks against email infrastructure, potentially affecting organizations that depend on automated spam filtering for their communication systems. The vulnerability demonstrates poor input validation and memory management practices that are consistent with common software security weaknesses documented in the CWE database under categories related to improper handling of memory operations and input validation failures.
The attack surface for this vulnerability is particularly concerning given that bogofilter is widely deployed in email security solutions and spam filtering systems. The remote nature of the exploit means that attackers can trigger the vulnerability without requiring local system access or authentication, making it especially dangerous in networked environments. This flaw aligns with ATT&CK technique T1499.004 for network denial of service attacks and represents a classic example of how seemingly benign input processing can become a vector for system compromise. Organizations using affected versions of bogofilter should immediately implement mitigations including software updates, input validation restrictions, and network-based filtering measures to prevent exploitation attempts. The vulnerability highlights the importance of proper memory management and input sanitization in security-critical applications, particularly those handling untrusted data from network sources.