Threat Brief: OWASSRF Vulnerability Exploitation
Unit 42 details active exploitation of Exchange SSRF flaws CVE-2022-41080/CVE-2022-41082 via the OWASSRF method, deploying the SilverArrow PowerShell backdoor.
Unit 42 documents OWASSRF, an exploit chain combining CVE-2022-41080 and CVE-2022-41082 to achieve remote code execution on Microsoft Exchange via Outlook Web Access, bypassing Microsoft's ProxyNotShell mitigations. Active exploitation was observed in late November and early December 2022, affecting at least eight organizations. Attackers authenticated to Exchange, then executed a PowerShell backdoor tracked as SilverArrow to create admin accounts, install AnyDesk, tunnel RDP via PuTTY Link, and dump LSASS memory for credential theft. Exploitation is isolated rather than mass-scale because authentication is required.
Another Apache Log4j Vulnerability Is Actively Exploited in the Wild (CVE-2021
Apache Log4j 2 RCE CVE-2021-44228 is actively exploited via crafted JNDI lookups; Palo Alto Unit 42 urges upgrading to Log4j 2.17.1.
Unit 42 details CVE-2021-44228, an easily exploited remote code execution flaw in Apache Log4j 2 where attacker-supplied JNDI lookups in logged user input cause payload download and execution. Massive internet-wide scanning for unpatched systems has begun, with observed follow-on activity including information stealing, Cobalt Strike delivery, and coinmining. The recommended fix is Log4j 2.17.1, which also patches CVE-2021-45046, CVE-2021-45105, and CVE-2021-44832. Widely used Java software including Apache Struts, Solr, Druid, Flink, ElasticSearch, and Spring Boot is affected.
Critical N-able N-central Vulnerability and Active Exploitation
N-able N-central pre-auth RCE zero-day CVE-2026-86218 (CVSS 10.0) is exploited in the wild; on-prem admins must upgrade to 2026.3 HF4.
N-able disclosed a third N-central vulnerability, CVE-2026-86218, a pre-authentication RCE rated CVSS 10.0, and released hotfix 2026.3 HF4 superseding build 2026.3.1.13. Huntress reproduced an exploit chain involving an authentication bypass (CVE-2026-86206/CVE-2026-86207) after a fully patched customer's N-central production server was compromised on September 4. Attackers appended strings like .invalid to account names and probed the /remoteControlAction.do?method=getPierDetails endpoint; Huntress worked with Cloudflare to disable adversary tunnel infrastructure. Hosted N-central instances are already patched; on-prem administrators must upgrade immediately.
CVE-2026-16232: Check Point SmartConsole Auth Bypass
Check Point SmartConsole authentication bypass CVE-2026-16232 grants unauthenticated attackers full admin access; actively exploited and added to CISA KEV.
CVE-2026-16232 is an improper authentication flaw (CWE-287) in the Check Point SmartConsole login process that lets an unauthenticated remote attacker obtain an application token and authenticate with full administrative privileges. Exploitation requires the Management Server to be internet-reachable and the Trusted Clients list not restricted to specific administrator addresses. Check Point confirmed active exploitation affecting a small number of customers, and the vulnerability has been added to the CISA Known Exploited Vulnerabilities catalog. A hotfix is available via Check Point advisory sk185169.
A Deep Dive Into Attempted Exploitation of CVE-2023
Mirai-like botnet scans exploit TP-Link EOL router flaw CVE-2023-33538 after CISA KEV addition, though observed exploit code is flawed.
Unit 42 observed large-scale automated scans attempting to exploit CVE-2023-33538 in end-of-life TP-Link TL-WR940N, TL-WR740N and TL-WR841N routers after CISA added the flaw to its KEV catalog in June 2025. HTTP GET requests inject commands via the ssid1 parameter at the /userRpm/WlanNetworkRpm endpoint to download and execute an arm7 ELF binary, a Mirai variant related to the Condi IoT botnet. Firmware emulation and reverse engineering showed the observed exploits are flawed and would fail, but the underlying vulnerability is real and successful exploitation requires authentication to the router's web interface. TP-Link confirmed the devices are end-of-life with no patches available and recommends replacing units and eliminating default credentials.
Attackers plant remote access tools on compromised PaperCut servers
Attackers chained two PaperCut NG/MF zero-days for unauthenticated access, installing SimpleHelp and AnyDesk remote access tools on compromised servers.
An ongoing campaign exploits chained zero-days CVE-2026-81578 (improper access control) and CVE-2026-82078 (unsafe dynamic class loading) in internet-facing PaperCut NG and MF Application Servers, enabling authentication bypass and arbitrary Java bytecode execution. Post-compromise activity includes user and domain enumeration, payload download from sendit.sh, and silent installation of SimpleHelp and AnyDesk for redundant remote access; Defused observed CVE-2026-81578/CVE-2026-82078 exploit activity in honeypots since August 29, including data theft via Derby database dumps. Emergency patches were released August 28 and August 30, but 47% of roughly 2,500 PaperCut installs tracked by Huntress run v23 or older, for which no patch is available.
U.S. CISA adds TrueConf Server flaws to its Known Exploited Vulnerabilities catalog
CISA added two exploited TrueConf Server flaws (CVE-2026-72529, CVE-2026-72530) to its KEV catalog with federal patch deadlines.
CISA added two TrueConf Server vulnerabilities to its Known Exploited Vulnerabilities catalog: CVE-2026-72529 (CVSS 9.3), a missing-authentication remote code execution flaw reachable on TCP port 4307, and CVE-2026-72530 (CVSS 9.5), a sandbox escape allowing code execution on the underlying host. Both flaws affect TrueConf Server versions 5.3.x through 5.5.5 and earlier, and were discovered by Vyacheslav Kopeytsev of Kaspersky ICS CERT. Under BOD 22-01, federal civilian agencies must patch CVE-2026-72529 by August 23, 2026, and CVE-2026-72530 by September 2, 2026.
Hackers Are Probing PaperCut Servers, and 47% Still Have No Patch
PaperCut pre-auth RCE CVE-2026-81578 actively exploited; 47% of tracked installs unpatched and exposed to remote code execution.
Huntress confirmed active exploitation of a pre-authentication RCE flaw in PaperCut (CVE-2026-81578), chainable with CVE-2026-82078 to achieve SYSTEM-level code execution via PaperCut's Application Server. Observed attacks focused on short reconnaissance (whoami, ver, tasklist) with no persistence, but a malicious Java class dropping into the installation directory leaves the jdbc:derby:memory:pwn breadcrumb. Roughly 47% of ~2,500 tracked installations run version 23 or earlier with no patch yet available.
Nearly 22,000 Microsoft Exchange servers remain exposed to critical security flaw (CVE-2026-62911)
About 22,000 Microsoft Exchange servers remain unpatched against critical auth bypass CVE-2026-62911 as a working exploit circulates online.
CVE-2026-62911 is a critical authentication bypass by capture-replay in Microsoft Exchange Server that allows an authorized attacker to elevate privileges over the network, with a CVSS score of 8.0. Microsoft patched the flaw on August 11, 2026, but Shadowserver Foundation scans show roughly 22,000 servers unpatched, with the US (6,200) and Germany (5,100) leading; BSI reports 85% of on-premises Exchange servers in Germany are still vulnerable. The Netherlands' NCSC-NL flagged that a working exploit is circulating, and Exchange 2016/2019 require the Extended Security Updates program for fixes.