CVE-2006-5903 in GSpace
Summary
by MITRE
Rahul Jonna Gmail File Space (GSpace) allows remote attackers to perform virtual filesystem actions via e-mail messages with certain subject lines, as demonstrated by (1) a GSPACE "2174|1|1|1|gs:/ d$" message, which injects a new file into the filesystem; and (2) a GSPACE "|-135|1|1|0|gs:/ d$" message, which creates a folder.
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Analysis
by VulDB Data Team • 04/27/2026
The vulnerability identified as CVE-2006-5903 represents a critical remote code execution flaw in Rahul Jonna's Gmail File Space (GSpace) application, which operates as a virtual filesystem interface integrated with email communication. This security weakness stems from insufficient input validation and sanitization mechanisms within the email processing pipeline, allowing malicious actors to manipulate the system through carefully crafted email subject lines that contain specific command sequences. The vulnerability specifically affects the way GSpace interprets and processes email messages containing filesystem manipulation instructions, creating a dangerous attack vector that bypasses traditional security controls.
The technical exploitation of this vulnerability occurs through the injection of specially formatted subject lines that contain command sequences designed to manipulate the virtual filesystem. The first demonstrated attack pattern involves a subject line containing "2174|1|1|1|gs:/ d$" which enables the injection of new files into the filesystem, while the second pattern uses "|-135|1|1|0|gs:/ d$" to create new directories or folders within the virtual filesystem structure. These command sequences are processed by the GSpace application without adequate validation, allowing attackers to execute arbitrary filesystem operations remotely. The vulnerability falls under CWE-20, which encompasses improper input validation, and demonstrates how insufficient sanitization of user-supplied data can lead to severe system compromise.
The operational impact of this vulnerability extends far beyond simple file manipulation, as it provides attackers with the capability to establish persistent access to the system and potentially escalate privileges through the creation of malicious files or directories. Attackers can leverage this vulnerability to plant backdoors, modify existing files, or create unauthorized access points within the virtual filesystem, effectively compromising the integrity and confidentiality of the entire system. The remote nature of the attack means that no local system access is required, making the vulnerability particularly dangerous as it can be exploited from anywhere on the internet. This type of vulnerability aligns with ATT&CK technique T1078 which covers valid accounts and T1059 for command and scripting interpreter, as the attack chain involves legitimate email protocols being abused for malicious command execution.
Mitigation strategies for this vulnerability require immediate implementation of input validation and sanitization measures within the GSpace application, including strict parsing of email subject lines and rejection of any sequences containing filesystem manipulation commands. Organizations should implement email filtering rules to block suspicious subject lines containing the specific patterns mentioned in the vulnerability description, while also deploying network monitoring solutions to detect anomalous email traffic patterns. The system should be updated to enforce proper authentication and authorization controls, ensuring that only legitimate users can perform filesystem operations, and regular security audits should be conducted to identify similar vulnerabilities in other email-based applications. Additionally, implementing a principle of least privilege for the GSpace application and maintaining comprehensive logging of all filesystem operations will help detect and respond to potential exploitation attempts.