CVE Vulnerabilities

CVE-2008-3075

Improper Control of Generation of Code ('Code Injection')

Published: Feb 21, 2009 | Modified: Sep 29, 2017
CVSS 3.x
N/A
Source:
NVD
CVSS 2.x
9.3 HIGH
AV:N/AC:M/Au:N/C:C/I:C/A:C
RedHat/V2
RedHat/V3
Ubuntu

The shellescape function in Vim 7.0 through 7.2, including 7.2a.10, allows user-assisted attackers to execute arbitrary code via the ! (exclamation point) shell metacharacter in (1) the filename of a ZIP archive and possibly (2) the filename of the first file in a ZIP archive, which is not properly handled by zip.vim in the VIM ZIP plugin (zipPlugin.vim) v.11 through v.21, as demonstrated by the zipplugin and zipplugin.v2 test cases. NOTE: this issue reportedly exists because of an incomplete fix for CVE-2008-2712. NOTE: this issue has the same root cause as CVE-2008-3074. NOTE: due to the complexity of the associated disclosures and the incomplete information related to them, there may be inaccuracies in this CVE description and in external mappings to this identifier.

Weakness

The software constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

Affected Software

Name Vendor Start Version End Version
Vim Vim 7.0 7.0
Vim Vim 7.1 7.1
Vim Vim 7.1.266 7.1.266
Vim Vim 7.1.314 7.1.314
Vim Vim 7.2 7.2
Vim Vim 7.2a.10 7.2a.10
Zipplugin.vim Vim v.11 v.11
Zipplugin.vim Vim v.12 v.12
Zipplugin.vim Vim v.13 v.13
Zipplugin.vim Vim v.14 v.14
Zipplugin.vim Vim v.15 v.15
Zipplugin.vim Vim v.16 v.16
Zipplugin.vim Vim v.17 v.17
Zipplugin.vim Vim v.18 v.18
Zipplugin.vim Vim v.19 v.19
Zipplugin.vim Vim v.20 v.20
Zipplugin.vim Vim v.21 v.21
Red Hat Enterprise Linux 5 RedHat vim-2:7.0.109-4.el5_2.4z *

Extended Description

When software allows a user’s input to contain code syntax, it might be possible for an attacker to craft the code in such a way that it will alter the intended control flow of the software. Such an alteration could lead to arbitrary code execution. Injection problems encompass a wide variety of issues – all mitigated in very different ways. For this reason, the most effective way to discuss these weaknesses is to note the distinct features which classify them as injection weaknesses. The most important issue to note is that all injection problems share one thing in common – i.e., they allow for the injection of control plane data into the user-controlled data plane. This means that the execution of the process may be altered by sending code in through legitimate data channels, using no other mechanism. While buffer overflows, and many other flaws, involve the use of some further issue to gain execution, injection problems need only for the data to be parsed. The most classic instantiations of this category of weakness are SQL injection and format string vulnerabilities.

Potential Mitigations

  • Run your code in a “jail” or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which code can be executed by your software.
  • Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection.
  • This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise.
  • Be careful to avoid CWE-243 and other weaknesses related to jails.
  • Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
  • When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
  • Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
  • To reduce the likelihood of code injection, use stringent allowlists that limit which constructs are allowed. If you are dynamically constructing code that invokes a function, then verifying that the input is alphanumeric might be insufficient. An attacker might still be able to reference a dangerous function that you did not intend to allow, such as system(), exec(), or exit().

References