Evidence used
- No CISA KEV confirmation is currently recorded.
- Exploitation requires an existing local or physical foothold with privileges.
- EPSS is 0.24% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2024
CVE-2023-52743High confidence
ice: Do not use WQ_MEM_RECLAIM flag for workqueue
Linux · Linux
5.5MediumCVSS 3.1
Patch only the product branches with a verified fix
Fix availability varies by productMedium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityMedium→Operational priority:Low, lowered one band.downgradedsince 11 May 2026
Compensating controls
- Validate the affected product branch and deploy the verified fixed release.
- Restrict local access and enforce least privilege on affected hosts.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs Linux Linux and falls inside the recorded affected range.
- Verify the installed build against the product-specific fixed version after deployment.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Remediation availability differs by product scope
Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
- Canonical Ubuntu Security: 1 affected package state with no published fix
Distribution package intelligence
5 package statesRelease-specific package status
Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.
Package result overrides the generic status
BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 1 affected package state shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.
Repository candidate not checked
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
| Distribution release | Source package | Vendor state | Fixed version | Evidence |
|---|---|---|---|---|
| Debian trixietrixie · source | linux | Vendor fix publishedDebian records a fixed source-package version for this release. | 6.1.12-1 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian bookwormbookworm · source | linux | Vendor fix publishedDebian records a fixed source-package version for this release. | 6.1.12-1 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian forkyforky · source | linux | Vendor fix publishedDebian records a fixed source-package version for this release. | 6.1.12-1 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian sidsid · source | linux | Vendor fix publishedDebian records a fixed source-package version for this release. | 6.1.12-1 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Ubuntu 24.04 LTSnoble · standard archive | linux-raspi-realtime | Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition. | Not published in this feed | Canonical Ubuntu Security ↗Source updated 5 Oct 2026 |
Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Fix availability varies by product01
What, why and how
In the Linux kernel, the following vulnerability has been resolved: ice: Do not use WQ_MEM_RECLAIM flag for workqueue When both ice and the irdma driver are loaded, a warning in check_flush_dependency is being triggered. This is due to ice driver workqueue being allocated with the WQ_MEM_RECLAIM flag and the irdma one is not. According to kernel documentation, this flag should be set if the workqueue will be involved in the kernel's memory reclamation flow. Since it is not, there is no need for the ice driver's WQ to have this flag set so remove it. Example trace: [ +0.000004] workqueue: WQ_MEM_RECLAIM ice:ice_service_task [ice] is flushing !WQ_MEM_RECLAIM infiniband:0x0 [ +0.000139] WARNING: CPU: 0 PID: 728 at kernel/workqueue.c:2632 check_flush_dependency+0x178/0x1a0 [ +0.000011] Modules linked in: bonding tls xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4 nft_compat nft_cha in_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables nfnetlink bridge stp llc rfkill vfat fat intel_rapl_msr intel _rapl_common isst_if_common skx_edac nfit libnvdimm x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irqbypass crct1 0dif_pclmul crc32_pclmul ghash_clmulni_intel rapl intel_cstate rpcrdma sunrpc rdma_ucm ib_srpt ib_isert iscsi_target_mod target_ core_mod ib_iser libiscsi scsi_transport_iscsi rdma_cm ib_cm iw_cm iTCO_wdt iTCO_vendor_support ipmi_ssif irdma mei_me ib_uverbs ib_core intel_uncore joydev pcspkr i2c_i801 acpi_ipmi mei lpc_ich i2c_smbus intel_pch_thermal ioatdma ipmi_si acpi_power_meter acpi_pad xfs libcrc32c sd_mod t10_pi crc64_rocksoft crc64 sg ahci ixgbe libahci ice i40e igb crc32c_intel mdio i2c_algo_bit liba ta dca wmi dm_mirror dm_region_hash dm_log dm_mod ipmi_devintf ipmi_msghandler fuse [ +0.000161] [last unloaded: bonding] [ +0.000006] CPU: 0 PID: 728 Comm: kworker/0:2 Tainted: G S 6.2.0-rc2_next-queue-13jan-00458-gc20aabd57164 #1 [ +0.000006] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0010.010620200716 01/06/2020 [ +0.000003] Workqueue: ice ice_service_task [ice] [ +0.000127] RIP: 0010:check_flush_dependency+0x178/0x1a0 [ +0.000005] Code: 89 8e 02 01 e8 49 3d 40 00 49 8b 55 18 48 8d 8d d0 00 00 00 48 8d b3 d0 00 00 00 4d 89 e0 48 c7 c7 e0 3b 08 9f e8 bb d3 07 01 <0f> 0b e9 be fe ff ff 80 3d 24 89 8e 02 00 0f 85 6b ff ff ff e9 06 [ +0.000004] RSP: 0018:ffff88810a39f990 EFLAGS: 00010282 [ +0.000005] RAX: 0000000000000000 RBX: ffff888141bc2400 RCX: 0000000000000000 [ +0.000004] RDX: 0000000000000001 RSI: dffffc0000000000 RDI: ffffffffa1213a80 [ +0.000003] RBP: ffff888194bf3400 R08: ffffed117b306112 R09: ffffed117b306112 [ +0.000003] R10: ffff888bd983088b R11: ffffed117b306111 R12: 0000000000000000 [ +0.000003] R13: ffff888111f84d00 R14: ffff88810a3943ac R15: ffff888194bf3400 [ +0.000004] FS: 0000000000000000(0000) GS:ffff888bd9800000(0000) knlGS:0000000000000000 [ +0.000003] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ +0.000003] CR2: 000056035b208b60 CR3: 000000017795e005 CR4: 00000000007706f0 [ +0.000003] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ +0.000003] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ +0.000002] PKRU: 55555554 [ +0.000003] Call Trace: [ +0.000002] <TASK> [ +0.000003] __flush_workqueue+0x203/0x840 [ +0.000006] ? mutex_unlock+0x84/0xd0 [ +0.000008] ? __pfx_mutex_unlock+0x10/0x10 [ +0.000004] ? __pfx___flush_workqueue+0x10/0x10 [ +0.000006] ? mutex_lock+0xa3/0xf0 [ +0.000005] ib_cache_cleanup_one+0x39/0x190 [ib_core] [ +0.000174] __ib_unregister_device+0x84/0xf0 [ib_core] [ +0.000094] ib_unregister_device+0x25/0x30 [ib_core] [ +0.000093] irdma_ib_unregister_device+0x97/0xc0 [irdma] [ +0.000064] ? __pfx_irdma_ib_unregister_device+0x10/0x10 [irdma] [ +0.000059] ? up_write+0x5c/0x90 [ +0.000005] irdma_remove+0x36/0x90 [irdma] [ +0.000062] auxiliary_bus_remove+0x32/0x50 [ +0.000007] device_r ---truncated---
What
In the Linux kernel, the following vulnerability has been resolved: ice: Do not use WQ_MEM_RECLAIM flag for workqueue When both ice and the irdma driver are loaded, a warning in check_flush_dependency is being triggered. This is due to ice driver workqueue being allocated with the WQ_MEM_RECLAIM flag and the irdma one is not. According to kernel documentation, this flag should be set if the workqueue will be involved in the kernel's memory reclamation flow. Since it is not, there is no need for the ice driver's WQ to have this flag set so remove it. Example trace: [ +0.000004] workqueue: WQ_MEM_RECLAIM ice:ice_service_task [ice] is flushing !WQ_MEM_RECLAIM infiniband:0x0 [ +0.000139] WARNING: CPU: 0 PID: 728 at kernel/workqueue.c:2632 check_flush_dependency+0x178/0x1a0 [ +0.000011] Modules linked in: bonding tls xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4 nft_compat nft_cha in_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables nfnetlink bridge stp llc rfkill vfat fat intel_rapl_msr intel _rapl_common isst_if_common skx_edac nfit libnvdimm x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irqbypass crct1 0dif_pclmul crc32_pclmul ghash_clmulni_intel rapl intel_cstate rpcrdma sunrpc rdma_ucm ib_srpt ib_isert iscsi_target_mod target_ core_mod ib_iser libiscsi scsi_transport_iscsi rdma_cm ib_cm iw_cm iTCO_wdt iTCO_vendor_support ipmi_ssif irdma mei_me ib_uverbs ib_core intel_uncore joydev pcspkr i2c_i801 acpi_ipmi mei lpc_ich i2c_smbus intel_pch_thermal ioatdma ipmi_si acpi_power_meter acpi_pad xfs libcrc32c sd_mod t10_pi crc64_rocksoft crc64 sg ahci ixgbe libahci ice i40e igb crc32c_intel mdio i2c_algo_bit liba ta dca wmi dm_mirror dm_region_hash dm_log dm_mod ipmi_devintf ipmi_msghandler fuse [ +0.000161] [last unloaded: bonding] [ +0.000006] CPU: 0 PID: 728 Comm: kworker/0:2 Tainted: G S 6.2.0-rc2_next-queue-13jan-00458-gc20aabd57164 #1 [ +0.000006] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0010.010620200716 01/06/2020 [ +0.000003] Workqueue: ice ice_service_task [ice] [ +0.000127] RIP: 0010:check_flush_dependency+0x178/0x1a0 [ +0.000005] Code: 89 8e 02 01 e8 49 3d 40 00 49 8b 55 18 48 8d 8d d0 00 00 00 48 8d b3 d0 00 00 00 4d 89 e0 48 c7 c7 e0 3b 08 9f e8 bb d3 07 01 <0f> 0b e9 be fe ff ff 80 3d 24 89 8e 02 00 0f 85 6b ff ff ff e9 06 [ +0.000004] RSP: 0018:ffff88810a39f990 EFLAGS: 00010282 [ +0.000005] RAX: 0000000000000000 RBX: ffff888141bc2400 RCX: 0000000000000000 [ +0.000004] RDX: 0000000000000001 RSI: dffffc0000000000 RDI: ffffffffa1213a80 [ +0.000003] RBP: ffff888194bf3400 R08: ffffed117b306112 R09: ffffed117b306112 [ +0.000003] R10: ffff888bd983088b R11: ffffed117b306111 R12: 0000000000000000 [ +0.000003] R13: ffff888111f84d00 R14: ffff88810a3943ac R15: ffff888194bf3400 [ +0.000004] FS: 0000000000000000(0000) GS:ffff888bd9800000(0000) knlGS:0000000000000000 [ +0.000003] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ +0.000003] CR2: 000056035b208b60 CR3: 000000017795e005 CR4: 00000000007706f0 [ +0.000003] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ +0.000003] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ +0.000002] PKRU: 55555554 [ +0.000003] Call Trace: [ +0.000002] <TASK> [ +0.000003] __flush_workqueue+0x203/0x840 [ +0.000006] ? mutex_unlock+0x84/0xd0 [ +0.000008] ? __pfx_mutex_unlock+0x10/0x10 [ +0.000004] ? __pfx___flush_workqueue+0x10/0x10 [ +0.000006] ? mutex_lock+0xa3/0xf0 [ +0.000005] ib_cache_cleanup_one+0x39/0x190 [ib_core] [ +0.000174] __ib_unregister_device+0x84/0xf0 [ib_core] [ +0.000094] ib_unregister_device+0x25/0x30 [ib_core] [ +0.000093] irdma_ib_unregister_device+0x97/0xc0 [irdma] [ +0.000064] ? __pfx_irdma_ib_unregister_device+0x10/0x10 [irdma] [ +0.000059] ? up_write+0x5c/0x90 [ +0.000005] irdma_remove+0x36/0x90 [irdma] [ +0.000062] auxiliary_bus_remove+0x32/0x50 [ +0.000007] device_r ---truncated---
Why
The current structured CVE record identifies a security weakness, but the root cause requires confirmation in the linked vendor material.
How
An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
In the Linux kernel, the following vulnerability has been resolved: ice: Do not use WQ_MEM_RECLAIM flag for workqueue When both ice and the irdma driver are loaded, a warning in check_flush_dependency is being triggered. This is due to ice driver workqueue being allocated with the WQ_MEM_RECLAIM flag and the irdma one is not. According to kernel documentation, this flag should be set if the workqueue will be involved in the kernel's memory reclamation flow. Since it is not, there is no need for the ice driver's WQ to have this flag set so remove it. Example trace: [ +0.000004] workqueue: WQ_MEM_RECLAIM ice:ice_service_task [ice] is flushing !WQ_MEM_RECLAIM infiniband:0x0 [ +0.000139] WARNING: CPU: 0 PID: 728 at kernel/workqueue.c:2632 check_flush_dependency+0x178/0x1a0 [ +0.000011] Modules linked in: bonding tls xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4 nft_compat nft_cha in_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables nfnetlink bridge stp llc rfkill vfat fat intel_rapl_msr intel _rapl_common isst_if_common skx_edac nfit libnvdimm x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irqbypass crct1 0dif_pclmul crc32_pclmul ghash_clmulni_intel rapl intel_cstate rpcrdma sunrpc rdma_ucm ib_srpt ib_isert iscsi_target_mod target_ core_mod ib_iser libiscsi scsi_transport_iscsi rdma_cm ib_cm iw_cm iTCO_wdt iTCO_vendor_support ipmi_ssif irdma mei_me ib_uverbs ib_core intel_uncore joydev pcspkr i2c_i801 acpi_ipmi mei lpc_ich i2c_smbus intel_pch_thermal ioatdma ipmi_si acpi_power_meter acpi_pad xfs libcrc32c sd_mod t10_pi crc64_rocksoft crc64 sg ahci ixgbe libahci ice i40e igb crc32c_intel mdio i2c_algo_bit liba ta dca wmi dm_mirror dm_region_hash dm_log dm_mod ipmi_devintf ipmi_msghandler fuse [ +0.000161] [last unloaded: bonding] [ +0.000006] CPU: 0 PID: 728 Comm: kworker/0:2 Tainted: G S 6.2.0-rc2_next-queue-13jan-00458-gc20aabd57164 #1 [ +0.000006] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0010.010620200716 01/06/2020 [ +0.000003] Workqueue: ice ice_service_task [ice] [ +0.000127] RIP: 0010:check_flush_dependency+0x178/0x1a0 [ +0.000005] Code: 89 8e 02 01 e8 49 3d 40 00 49 8b 55 18 48 8d 8d d0 00 00 00 48 8d b3 d0 00 00 00 4d 89 e0 48 c7 c7 e0 3b 08 9f e8 bb d3 07 01 <0f> 0b e9 be fe ff ff 80 3d 24 89 8e 02 00 0f 85 6b ff ff ff e9 06 [ +0.000004] RSP: 0018:ffff88810a39f990 EFLAGS: 00010282 [ +0.000005] RAX: 0000000000000000 RBX: ffff888141bc2400 RCX: 0000000000000000 [ +0.000004] RDX: 0000000000000001 RSI: dffffc0000000000 RDI: ffffffffa1213a80 [ +0.000003] RBP: ffff888194bf3400 R08: ffffed117b306112 R09: ffffed117b306112 [ +0.000003] R10: ffff888bd983088b R11: ffffed117b306111 R12: 0000000000000000 [ +0.000003] R13: ffff888111f84d00 R14: ffff88810a3943ac R15: ffff888194bf3400 [ +0.000004] FS: 0000000000000000(0000) GS:ffff888bd9800000(0000) knlGS:0000000000000000 [ +0.000003] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ +0.000003] CR2: 000056035b208b60 CR3: 000000017795e005 CR4: 00000000007706f0 [ +0.000003] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ +0.000003] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ +0.000002] PKRU: 55555554 [ +0.000003] Call Trace: [ +0.000002] <TASK> [ +0.000003] __flush_workqueue+0x203/0x840 [ +0.000006] ? mutex_unlock+0x84/0xd0 [ +0.000008] ? __pfx_mutex_unlock+0x10/0x10 [ +0.000004] ? __pfx___flush_workqueue+0x10/0x10 [ +0.000006] ? mutex_lock+0xa3/0xf0 [ +0.000005] ib_cache_cleanup_one+0x39/0x190 [ib_core] [ +0.000174] __ib_unregister_device+0x84/0xf0 [ib_core] [ +0.000094] ib_unregister_device+0x25/0x30 [ib_core] [ +0.000093] irdma_ib_unregister_device+0x97/0xc0 [irdma] [ +0.000064] ? __pfx_irdma_ib_unregister_device+0x10/0x10 [irdma] [ +0.000059] ? up_write+0x5c/0x90 [ +0.000005] irdma_remove+0x36/0x90 [irdma] [ +0.000062] auxiliary_bus_remove+0x32/0x50 [ +0.000007] device_r ---truncated---
Why
The current structured CVE record identifies a security weakness, but the root cause requires confirmation in the linked vendor material.
How
An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
- Likely attack path
- local access → vulnerable operation → cause the confidentiality, integrity or availability impact described by the vendor
- Attack surface
- Local
- Privileges required
- Low: a basic authenticated account is required
- User interaction
- None
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Unchanged: impact remains within the vulnerable component's security authority
- Weakness
?
CWE means Common Weakness Enumeration. - CWE not yet assigned
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.- Post-exploitation / living off the land
- The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
03
Patch and workaround
Operational remediation based on structured source evidence.
- Status
?
Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change. - Fix availability varies by product
- Action
- Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
- Workaround
- No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04
Evidence and provenance
Published 21 May 2024 · Last source change 11 May 2026, 19:32 UTC · CWE not yet assigned
CVE recordCVE.org · 5.2
CVSS sourceNIST NVD
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2023-59462
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceUnavailable
NVD statusNVD enriched
Missing structured fields: CWE classification. Missing data is not evidence of low risk; review the primary advisory.
Material change intelligence
View recent updates ↗What changed after publication
No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.
CVE published
Fixed release or patch reference recorded
Technical terms and abbreviations used in this report
- CVE
- Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
- CVSS
- Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
- EPSS
- Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
- CWE
- Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
- CNA
- CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
- CISA ADP
- Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
- NVD
- National Vulnerability Database: NIST's enrichment service for CVE records.
- CERT / CSIRT
- A computer security incident response team that publishes warnings or coordinates incident response.
- PoC
- Proof of concept: public material that demonstrates or helps reproduce exploitation.
- CSAF
- Common Security Advisory Framework: a machine-readable format for security advisories.
- LoTL
- Living off the land: abuse of legitimate tools or system functions during an attack.