CVE-2011-3630 in Hardlink
Summary
by MITRE
Hardlink before 0.1.2 suffer from multiple stack-based buffer overflow flaws because of the way directory trees with deeply nested directories are processed. A remote attacker could provide a specially-crafted directory tree, and trick the local user into consolidating it, leading to hardlink executable crash, or, potentially arbitrary code execution with the privileges of the user running the hardlink executable.
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Analysis
by VulDB Data Team • 02/27/2024
The vulnerability identified as CVE-2011-3630 affects the hardlink utility version 0.1.1 and earlier, presenting critical stack-based buffer overflow flaws that arise during the processing of deeply nested directory structures. This flaw represents a classic software security vulnerability where improper input validation leads to memory corruption, specifically targeting the stack memory area of the executing process. The vulnerability stems from the utility's inadequate handling of directory tree traversal operations, particularly when encountering deeply nested directory hierarchies that exceed the allocated buffer space.
The technical implementation of this vulnerability involves the hardlink utility's recursive directory processing algorithm failing to properly validate the depth of directory nesting before attempting to store path information in stack buffers. When a maliciously crafted directory tree is presented to the utility, the recursive traversal function accumulates path components in a fixed-size stack buffer without sufficient bounds checking. This allows an attacker to overflow the buffer and overwrite adjacent stack memory, potentially corrupting the return address or other critical program state information. The flaw manifests when the local user executes the hardlink command on a specially crafted directory structure, creating a scenario where the attacker's control over the input directly translates to control over the program execution flow.
The operational impact of this vulnerability extends beyond simple application crashes to potentially enable arbitrary code execution with the privileges of the user running the hardlink utility. This represents a privilege escalation vector that could be exploited by remote attackers to gain unauthorized access to systems where the vulnerable utility is present. The vulnerability is particularly concerning because it requires user interaction to be exploited, making it a form of social engineering attack that combines technical exploitation with user deception. The attack scenario involves an attacker providing a malicious directory tree structure that, when processed by the vulnerable hardlink utility, results in the execution of arbitrary code with the user's privileges.
The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite stack memory. This flaw also demonstrates characteristics consistent with ATT&CK technique T1059, where adversaries leverage command-line interfaces to execute malicious code, and T1068, which involves privilege escalation through exploitation of software vulnerabilities. The attack vector is classified as a local privilege escalation vulnerability since it requires user interaction but can result in execution with elevated privileges. The exploitability of this vulnerability is enhanced by the fact that the hardlink utility is commonly available on Unix-like systems, making it a potentially widespread target for exploitation. Organizations should implement immediate mitigations including updating to hardlink version 0.1.2 or later, which contains proper bounds checking for directory traversal operations, and implementing user education to avoid processing untrusted directory structures. Additionally, system administrators should consider restricting the execution of hardlink in environments where untrusted directory trees may be encountered, and monitor for suspicious directory creation patterns that could indicate exploitation attempts.