CVE-2017-12588 in rsyslog
Summary
by MITRE
The zmq3 input and output modules in rsyslog before 8.28.0 interpreted description fields as format strings, possibly allowing a format string attack with unspecified impact.
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Analysis
by VulDB Data Team • 12/27/2024
The vulnerability identified as CVE-2017-12588 affects rsyslog versions prior to 8.28.0, specifically within the zmq3 input and output modules. This issue represents a classic format string vulnerability that arises from improper handling of user-supplied data within the logging framework. The flaw occurs when the system processes description fields that are interpreted as format strings rather than literal text, creating potential attack vectors for malicious actors who can manipulate log data to execute unintended operations.
The technical implementation of this vulnerability stems from the rsyslog zmq3 modules failing to properly sanitize or escape description fields before processing them as format strings. When these modules encounter user-provided data containing format specifiers such as %s, %d, or %x, they interpret these as instructions for formatting output rather than literal characters. This misinterpretation allows attackers to inject malicious format specifiers that can trigger various exploitable conditions including information disclosure, application crashes, or potentially arbitrary code execution depending on the system configuration and memory layout.
From an operational perspective, this vulnerability poses significant risks to systems relying on rsyslog for centralized logging and message queuing through zeromq. The unspecified impact mentioned in the CVE description suggests that the attack surface could encompass multiple attack vectors including denial of service through application crashes, information leakage through memory dumps, or in some configurations, privilege escalation. The vulnerability is particularly concerning because it operates at the logging layer where attackers might have access to various input sources that feed into the rsyslog system, including network services, applications, or even compromised systems that send log data.
The attack patterns associated with this vulnerability align with standard format string exploitation techniques documented in the CWE-134 category, which specifically addresses the use of untrusted data in format string operations. This vulnerability also maps to several ATT&CK techniques including T1070.004 for indicator removal and T1059.007 for command and scripting interpreter, as attackers could potentially use format string exploits to gain unauthorized access to system resources or manipulate log data to hide malicious activities. The impact extends beyond simple logging functions as compromised rsyslog instances could affect security monitoring, forensic analysis, and overall system integrity.
Mitigation strategies for CVE-2017-12588 primarily involve upgrading to rsyslog version 8.28.0 or later where the vulnerability has been addressed through proper input sanitization and format string handling. Organizations should also implement input validation measures at the network level to prevent malicious data from reaching the logging system, particularly in environments where untrusted sources contribute to log data streams. Additional defensive measures include monitoring for unusual log patterns that might indicate exploitation attempts, implementing proper access controls to restrict who can submit data to the rsyslog system, and conducting regular security assessments of logging infrastructure to identify similar vulnerabilities in other components of the security ecosystem.