CVE-2012-6711
Description
A heap-based buffer overflow was discovered in bash when wide characters, not supported by the current locale set in LC_CTYPE environment variable, are printed through the echo built-in function. A local attacker, who can provide data to print through the echo -e built-in function, may use this flaw to crash a script or execute code with the privileges of the bash process.
Déclaration
Impact set to Moderate as the flaw requires the usage of echo -e built-in function with a string controlled by the attacker. Abusing this flaw would allow an attacker to, at most, execute code with the privileges of the bash process, which could be used e.g. to escape a restricted shell in case of a local attacker scenario or remotely execute code in case of a bash script that accepts untrusted input from the network. However we do not recommend to use bash scripts to handle untrusted data from the network.
Détails du score du système commun d'évaluation des vulnérabilités (CVSS)
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
Les mesures et les scores CVSS suivants sont préliminaires et sujets à révision.
Répartition des scores CVSS v3
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Score de base | 7 | 7.8 | N/A |
| Vecteur d'attaque | Local | Local | N/A |
| Complexité de l'attaque | High | Low | N/A |
| Privilèges requis | Low | Low | N/A |
| Interaction avec l'utilisateur | None | None | N/A |
| Champ d'application | Unchanged | Unchanged | N/A |
| Confidentialité | High | High | N/A |
| Impact sur l'intégrité | High | High | N/A |
| Impact sur la disponibilité | High | High | N/A |
Vecteur
Red Hat: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Explication du score CVSS v3 de Red Hat
Attack Complexity (AC) set to High (H) as the flaw requires the use the echo built-in function with the -e option, which allows you to print unicode characters given the right bytes values, and an attacker controlled string passed as input. Moreover, mitigations such as ASLR are in place, making a full attack harder.
Comprendre la Défaillance (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
Buffer overflows generally lead to crashes. Other attacks leading to lack of availability are possible, including putting the program into an infinite loop.
Integrity,Confidentiality,Availability,Access Control
Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism; Modify Memory
Buffer overflows often can be used to execute arbitrary code, which is usually outside the scope of a program's implicit security policy. Besides important user data, heap-based overflows can be used to overwrite function pointers that may be living in memory, pointing it to the attacker's code. Even in applications that do not explicitly use function pointers, the run-time will usually leave many in memory. For example, object methods in C++ are generally implemented using function pointers. Even in C programs, there is often a global offset table used by the underlying runtime.
Integrity,Confidentiality,Availability,Access Control,Other
Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism; Other
When the consequence is arbitrary code execution, this can often be used to subvert any other security service.
Remerciements
Red Hat would like to thank Erez Turjeman for reporting this issue.
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