CVE-2021-4034
CVE-2021-4034: 2 tracked advisory records across Commvault, Red Hat. CISA KEV listed; exploitation observed. Compare vendor sources and published fix guidance.
Compare the source-linked records below. Ratings and product/version details belong to each advisory; they are not a single CVE-wide score or proof that every listed product is affected. How VulniPulse collects and checks evidence.
Vendor advisory comparison
Commvault
1 advisory- Advisory severityHigh
High [CVE-2021-4034] Local Privilege Escalation Vulnerability in Polkit's pkexec Utility
CV_2022_01_1Source published
Local Privilege Escalation Vulnerability in Polkit's pkexec Utility
- Related products — impact not confirmed
- No product details extracted. Check the source bulletin.
- Source-reported affected versions
- The vulnerability may affect the Commvault Hyperscale products.
- Source-reported fixed versions
- No fixed-version detail extracted. This does not mean no fix exists.
- Mitigation guidance
- No mitigation guidance extracted; consult the source.
Red Hat
1 advisory- Advisory severityHigh7.8
High [CVE-2021-4034] local privilege escalation vulnerability was found on polkit's pkexec utility
CVE-2021-4034Source published Source updated
A local privilege escalation vulnerability was found on polkit's pkexec utility. The pkexec application is a setuid tool designed to allow unprivileged users to run commands as privileged users according predefined policies. The current version of pkexec doesn't handle the calling parameters count correctly and ends trying to execute environment variables as commands. An attacker can leverage this by crafting environment variables in such a way it'll induce pkexec to execute arbitrary code. When successfully executed the attack can cause a local privilege escalation given unprivileged users administrative rights on the target machine. Red Hat severity: Important — CVSS 7.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H). Weakness: CWE-787.
- Affected products in this advisory
- Red Hat Enterprise Linux 6 Extended Lifecycle Support
- Red Hat Enterprise Linux 7.3 Advanced Update Support
- Red Hat Enterprise Linux 7.4 Advanced Update Support
- Red Hat Enterprise Linux 7.6 Advanced Update Support
11 more entries in the full advisory.
- Source-reported affected versions
- Affected-version details not available in this record.
- Source-reported fixed versions
- polkit-0:0.96-11.el6_10.2
- polkit-0:0.112-26.el7_9.1
- polkit-0:0.112-12.el7_3.1
- polkit-0:0.112-12.el7_4.2
20 more entries in the full advisory.
- Mitigation guidance
- For customers who cannot update immediately and doesn't have Secure Boot feature enabled, the issue can be mitigated by executing the following steps: 1) Install required systemtap packages and dependencies as per - pointed by https://access.redhat.com/solutions/5441 2) Install polkit debug info: ~~~ debuginfo-install polkit ~~~ 3) Create the following systemtap script, and name it pkexec-block.stp: ~~~ probe process("/usr/bin/pkexec").function("main") { if (cmdline_arg(1) == "") raise(9); } ~~~ 4) Load the systemtap module into the running kernel: ~~~ stap -g -F -m stap_pkexec_block pkexec_block.stp ~~~ 5) Ensure the module is loaded: ~~~ lsmod | grep -i stap_pkexec_block stap_pkexec_block 434176 0 ~~~ 6) Once polkit package was updated to the version containing the fix, the systemtap generated kernel module can be removed by running: ~~~ rmmod stap_pkexec_block ~~~ This mitigation doesn't work for Secure Boot enabled system as SystemTap would require an external compiling server to be able to sign the generated kernel module with a key enrolled into the Kernel's keyring.
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