An issue was discovered in Adobe Acrobat and Reader: 2017.012.20098 and earlier versions, 2017.011.30066 and earlier versions, 2015.006.30355 and earlier versions, and 11.0.22 and earlier versions. This vulnerability is an instance of a type confusion vulnerability in the EMF processing module. The issue causes the program to access an object using an incompatible type, leading to an out of bounds memory access. Attackers can exploit the vulnerability by using the out of bounds access for unintended reads, writes, or frees – potentially leading to code corruption, control-flow hijack, or information leak attack.
Weakness
The product reads data past the end, or before the beginning, of the intended buffer.
Affected Software
| Name |
Vendor |
Start Version |
End Version |
| Acrobat |
Adobe |
* |
11.0.22 (including) |
| Acrobat |
Adobe |
17.0 (including) |
17.011.30066 (including) |
| Acrobat_dc |
Adobe |
- (including) |
17.012.20098 (including) |
| Acrobat_dc |
Adobe |
15.0 (including) |
15.006.30355 (including) |
| Acrobat_reader |
Adobe |
* |
11.0.22 (including) |
| Acrobat_reader |
Adobe |
17.0 (including) |
17.011.30066 (including) |
| Acrobat_reader_dc |
Adobe |
- (including) |
17.012.20098 (including) |
| Acrobat_reader_dc |
Adobe |
15.0 (including) |
15.006.30355 (including) |
Potential Mitigations
- 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 introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.
References