CVE-2021-34552
Description
A flaw was found in python-pillow. This flaw allows an attacker to pass controlled parameters directly into a convert function, triggering a buffer overflow in the "convert()" or "ImagingConvertTransparent()" functions in Convert.c. The highest threat to this vulnerability is to system availability.
In Red Hat Quay, a vulnerable version of python-pillow is shipped with quay-registry-container, however the invoice generation feature which uses python-pillow is disabled by default. Therefore impact has been rated Moderate.
Statement
Due to the compiler options used, the buffer overflow is detected and the impact is lowered to a crash only. Additionally, the "mode" parameter has to be attacker controlled, which is considered a rare case.
Mitigation
To mitigate this flaw on Red Hat Quay, keep the invoice generation feature disabled, as it is by default.
Red Hat Satellite 6.9 customers can apply following hotfix to eliminate the vulnerability warnings.
* Download python2-daemon-2.1.2-7.1.HFRHBZ1998199.el7sat.noarch.rpm from https://bugzilla.redhat.com/attachment.cgi?id=1819471
* Stop services:
# satellite-maintain service stop
* Upgrade python2-daemon and remove affected package
# rpm -Uvh python2-daemon-2.1.2-7.1.HFRHBZ1998199.el7sat.noarch.rpm
# yum remove python-pillow
* Restart services:
# satellite-maintain service start
Satellite 6.10 future release is also fixing this.
Common Vulnerability Scoring System (CVSS) Score Details
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.9 | 9.8 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | High | N/A |
| Integrity Impact | None | High | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Red Hat CVSS v3 Score Explanation
Due to the compiler options used, the impact of this vulnerability is lowered to a crash only, thus 'Confidentiality' and 'Integrity' is set to none, but 'Availability' is set to high. Additionally, the "mode" parameter passed to the vulnerable convert function has to be attacker controlled, which is considered to be a rather rare case. Thus, 'Access complexity' has been set to high.
Understanding the Weakness (CWE)
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands; Modify Memory
If the memory accessible by the attacker can be effectively controlled, it may be possible to execute arbitrary code, as with a standard buffer overflow. If the attacker can overwrite a pointer's worth of memory (usually 32 or 64 bits), they can alter the intended control flow by redirecting a function pointer to their own malicious code. Even when the attacker can only modify a single byte arbitrary code execution can be possible. Sometimes this is because the same problem can be exploited repeatedly to the same effect. Other times it is because the attacker can overwrite security-critical application-specific data -- such as a flag indicating whether the user is an administrator.
Availability,Confidentiality
Technical Impact: Read Memory; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
Out of bounds memory access will very likely result in the corruption of relevant memory, and perhaps instructions, possibly leading to a crash. Other attacks leading to lack of availability are possible, including putting the program into an infinite loop.
Confidentiality
Technical Impact: Read Memory
In the case of an out-of-bounds read, the attacker may have access to sensitive information. If the sensitive information contains system details, such as the current buffer's position in memory, this knowledge can be used to craft further attacks, possibly with more severe consequences.
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