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medium advisory

cURL Vulnerability Allows File Manipulation

A remote, anonymous attacker can exploit a vulnerability in cURL to manipulate files on a vulnerable system.

A vulnerability exists in cURL that allows a remote, anonymous attacker to manipulate files. The BSI advisory indicates that this vulnerability could be exploited without authentication, potentially leading to unauthorized modifications of sensitive data or system configuration. While the specific details of the vulnerability and exploitation methods are not provided in the advisory, the potential for file manipulation highlights the importance of timely patching and monitoring of cURL installations. This vulnerability impacts systems using the affected versions of cURL, potentially affecting a wide range of applications and services.

Attack Chain

  1. The attacker identifies a vulnerable system running an affected version of cURL.
  2. The attacker crafts a malicious request to exploit the cURL vulnerability. Due to the lack of specifics in the advisory, the nature of this request is unknown, but may involve specially crafted URLs or command-line arguments.
  3. cURL processes the malicious request, triggering the vulnerability. This could involve writing to unintended file paths or modifying file contents.
  4. The attacker leverages the vulnerability to modify critical system files.
  5. The attacker uses the file manipulation to gain unauthorized access or escalate privileges.
  6. The attacker maintains persistence on the compromised system.
  7. The attacker performs malicious activities such as data exfiltration or denial of service.

Impact

Successful exploitation of this cURL vulnerability could lead to unauthorized file modifications, potentially affecting system stability, data integrity, and confidentiality. The scope of the impact depends on the specific files manipulated by the attacker. System compromise and data breaches are potential consequences.

Recommendation

  • Monitor network traffic for suspicious cURL activity, specifically command line arguments that attempt to write to or modify system files. Use the process creation rule below to identify unusual invocations (Rules: “Detect Suspicious cURL File Writes”).
  • Update cURL to the latest version to remediate any known vulnerabilities after vendor releases a patch.
  • Implement file integrity monitoring (FIM) to detect unauthorized changes to critical system files.

Detection coverage 2

Detect Suspicious cURL File Writes

high

Detects cURL commands attempting to write to sensitive file paths.

sigma tactics: persistence, privilege_escalation techniques: T1548.001 sources: process_creation, linux

Detect cURL with Suspicious Output Redirection to Hidden Files

medium

Detects cURL commands attempting to write to hidden files with output redirection, potentially indicating malicious activity.

sigma tactics: defense_evasion techniques: T1070.001 sources: process_creation, linux

Detection queries are kept inside the platform. Get full rules →