USN-5829-1: Linux kernel (Raspberry Pi) vulnerabilities

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It was discovered that the NFSD implementation in the Linux kernel did not
properly handle some RPC messages, leading to a buffer overflow. A remote
attacker could use this to cause a denial of service (system crash) or
possibly execute arbitrary code. (CVE-2022-43945)

Tamás Koczka discovered that the Bluetooth L2CAP handshake implementation
in the Linux kernel contained multiple use-after-free vulnerabilities. A
physically proximate attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2022-42896)

It was discovered that the Xen netback driver in the Linux kernel did not
properly handle packets structured in certain ways. An attacker in a guest
VM could possibly use this to cause a denial of service (host NIC
availability). (CVE-2022-3643)

It was discovered that an integer overflow vulnerability existed in the
Bluetooth subsystem in the Linux kernel. A physically proximate attacker
could use this to cause a denial of service (system crash).
(CVE-2022-45934)

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USN-5828-1: Kerberos vulnerabilities

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It was discovered that Kerberos incorrectly handled certain S4U2Self
requests. An attacker could possibly use this issue to cause a denial of
service. This issue was only addressed in Ubuntu 16.04 ESM and Ubuntu
18.04 LTS. (CVE-2018-20217)

Greg Hudson discovered that Kerberos PAC implementation incorrectly
handled certain parsing operations. A remote attacker could use this
issue to cause a denial of service, or possibly execute arbitrary code.
(CVE-2022-42898)

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Experian Glitch Exposing Credit Files Lasted 47 Days

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On Dec. 23, 2022, KrebsOnSecurity alerted big-three consumer credit reporting bureau Experian that identity thieves had worked out how to bypass its security and access any consumer’s full credit report — armed with nothing more than a person’s name, address, date of birth, and Social Security number. Experian fixed the glitch, but remained silent about the incident for a month. This week, however, Experian acknowledged that the security failure persisted for nearly seven weeks, between Nov. 9, 2022 and Dec. 26, 2022.

The tip about the Experian weakness came from Jenya Kushnir, a security researcher living in Ukraine who said he discovered the method being used by identity thieves after spending time on Telegram chat channels dedicated to cybercrime.

Normally, Experian’s website will ask a series of multiple-choice questions about one’s financial history, as a way of validating the identity of the person requesting the credit report. But Kushnir said the crooks learned they could bypass those questions and trick Experian into giving them access to anyone’s credit report, just by editing the address displayed in the browser URL bar at a specific point in Experian’s identity verification process.

When I tested Kushnir’s instructions on my own identity at Experian, I found I was able to see my report even though Experian’s website told me it didn’t have enough information to validate my identity. A security researcher friend who tested it at Experian found she also could bypass Experian’s four or five multiple-choice security questions and go straight to her full credit report at Experian.

Experian acknowledged receipt of my Dec. 23 report four days later on Dec. 27, a day after Kushnir’s method stopped working on Experian’s website (the exploit worked as long as you came to Experian’s website via annualcreditreport.com — the site mandated to provide a free copy of your credit report from each of the major bureaus once a year).

Experian never did respond to official requests for comment on that story. But earlier this week, I received an otherwise unhelpful letter via snail mail from Experian (see image above), which stated that the weakness we reported persisted between Nov. 9, 2022 and Dec. 26, 2022.

“During this time period, we experienced an isolated technical issue where a security feature may not have functioned,” Experian explained.

It’s not entirely clear whether Experian sent me this paper notice because they legally had to, or if they felt I deserved a response in writing and thought maybe they’d kill two birds with one stone. But it’s pretty crazy that it took them a full month to notify me about the potential impact of a security failure that I notified them about.

It’s also a little nuts that Experian didn’t simply include a copy of my current credit report along with this letter, which is confusingly worded and reads like they suspect someone other than me may have been granted access to my credit report without any kind of screening or authorization.

After all, if I hadn’t authorized the request for my credit file that apparently prompted this letter (I had), that would mean the thieves already had my report. Shouldn’t I be granted the same visibility into my own credit file as them?

Instead, their woefully inadequate letter once again puts the onus on me to wait endlessly on hold for an Experian representative over the phone, or sign up for a free year’s worth of Experian monitoring my credit report.

As it stands, using Kushnir’s exploit was the only time I’ve ever been able to get Experian’s website to cough up a copy of my credit report. To make matters worse, a majority of the information in that credit report is not mine. So I’ve got that to look forward to.

If there is a silver lining here, I suppose that if I were Experian, I probably wouldn’t want to show Brian Krebs his credit file either. Because it’s clear this company has no idea who I really am. And in a weird, kind of sad way I guess, that makes me happy.

For thoughts on what you can do to minimize your victimization by and overall worth to the credit bureaus, see this section of the most recent Experian story.

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Attackers move away from Office macros to LNK files for malware delivery

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For years attackers have used Office documents with malicious macros as one of the primary methods of infecting computers with malware. Microsoft finally took steps to disable such scripts by default in documents downloaded from the internet, forcing many groups to change tactics and increasingly choose LNK (shortcut) files as a delivery mechanism.

This trend has led to the creation of paid tools and services dedicated to building malicious LNK files. Some of these builders include MLNK Builder, Quantum Builder, Macropack, LNKUp, Lnk2pwn, SharPersist, and RustLnkBuilder, but their use can provide opportunities for easier detection by security products.

To read this article in full, please click here

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USN-5827-1: Bind vulnerabilities

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Rob Schulhof discovered that Bind incorrectly handled a large number of
UPDATE messages. A remote attacker could possibly use this issue to cause
Bind to consume resources, resulting in a denial of service.
(CVE-2022-3094)

Borja Marcos discovered that Bind incorrectly handled certain RRSIG
queries. A remote attacker could possibly use this issue to cause Bind to
crash, resulting in a denial of service. This issue only affected Ubuntu
22.04 LTS and Ubuntu 22.10. (CVE-2022-3736)

Maksym Odinintsev discovered that Bind incorrectly handled certain answers
from stale cache. A remote attacker could possibly use this issue to cause
Bind to crash, resulting in a denial of service. This issue only affected
Ubuntu 22.04 LTS and Ubuntu 22.10. (CVE-2022-3924)

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