CVE-2015-1548 in Mini HTTPd
Summary
by MITRE
mini_httpd 1.21 and earlier allows remote attackers to obtain sensitive information from process memory via an HTTP request with a long protocol string, which triggers an incorrect response size calculation and an out-of-bounds read.
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Analysis
by VulDB Data Team • 06/21/2018
The vulnerability identified as CVE-2015-1548 affects mini_httpd version 1.21 and earlier, representing a critical information disclosure flaw that stems from improper handling of HTTP protocol strings. This vulnerability resides within the HTTP server implementation where the software fails to properly validate the length of protocol strings submitted in HTTP requests. The flaw manifests when an attacker crafts a malicious HTTP request containing an excessively long protocol string, which then triggers a cascading error in the server's memory management routines. The root cause lies in the software's inadequate boundary checking mechanisms that fail to prevent buffer overflows or out-of-bounds memory access during request processing. This vulnerability directly maps to CWE-125, which describes out-of-bounds read conditions in software implementations, and also aligns with CWE-20, representing improper input validation that allows attackers to manipulate program execution flow through malformed data.
The technical exploitation of this vulnerability occurs through a carefully constructed HTTP request that includes a protocol string exceeding normal boundaries. When the mini_httpd server processes this malformed request, it calculates a response size based on incorrect assumptions about the input data length. This miscalculation leads to the server attempting to read memory locations beyond the intended buffer boundaries, inadvertently exposing sensitive data from adjacent memory regions. The out-of-bounds read operation may retrieve various types of sensitive information including but not limited to authentication tokens, session identifiers, cryptographic keys, system memory contents, or other confidential data that happens to reside in the memory space adjacent to the vulnerable buffer. This type of information disclosure represents a significant threat to system security as it can provide attackers with enough data to escalate privileges, bypass authentication mechanisms, or conduct further exploitation attempts.
The operational impact of CVE-2015-1548 extends beyond simple information disclosure, as it creates opportunities for attackers to gather intelligence that can facilitate more sophisticated attacks. An attacker who successfully exploits this vulnerability can potentially extract system memory contents that may include cached passwords, database connection strings, or other sensitive application data that could be leveraged for privilege escalation or lateral movement within a network. The vulnerability's remote nature means that attackers can exploit it without requiring physical access or local system credentials, making it particularly dangerous in internet-facing environments. From an attacker's perspective, this vulnerability aligns with techniques described in the ATT&CK framework under the Information Gathering phase, where adversaries collect information about the target system to inform subsequent attack phases. The vulnerability also relates to the Credential Access and Discovery tactics, as sensitive data exposure can lead to authentication bypasses and system reconnaissance activities.
Mitigation strategies for CVE-2015-1548 focus primarily on updating to patched versions of mini_httpd where the protocol string validation has been properly implemented. Organizations should immediately upgrade to mini_httpd version 1.22 or later, where the buffer overflow conditions have been addressed through proper input validation and memory boundary checks. Additionally, implementing network-level protections such as intrusion detection systems can help detect and block malicious HTTP requests containing excessively long protocol strings. Configuration hardening measures should include setting appropriate limits on HTTP header sizes and implementing rate limiting to prevent abuse of the vulnerability. Security monitoring should be enhanced to detect unusual memory access patterns or abnormal HTTP request characteristics that may indicate exploitation attempts. The vulnerability also highlights the importance of proper input validation and defensive programming practices, particularly in network services that handle untrusted data from external sources. Organizations should conduct regular security assessments of their web server configurations and ensure that all third-party software components are kept up to date with the latest security patches to prevent similar vulnerabilities from being exploited in their environments.