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The Hacker News - Cybersecurity News and Analysis: digital signature

Digital Signature Spoofing Flaws Uncovered in OpenOffice and LibreOffice

Digital Signature Spoofing Flaws Uncovered in OpenOffice and LibreOffice

October 12, 2021Ravie Lakshmanan
The maintainers of LibreOffice and OpenOffice have shipped security updates to their productivity software to remediate multiple vulnerabilities that could be weaponized by malicious actors to alter documents to make them appear as if they are digitally signed by a trusted source. The list of the three flaws is as follows — CVE-2021-41830  /  CVE-2021-25633  - Content and Macro Manipulation with Double Certificate Attack CVE-2021-41831  /  CVE-2021-25634  - Timestamp Manipulation with Signature Wrapping CVE-2021-41832  /  CVE-2021-25635  - Content Manipulation with Certificate Validation Attack Successful exploitation of the vulnerabilities could permit an attacker to  manipulate the timestamp  of signed ODF documents, and worse,  alter the contents  of a document or  self-sign a document  with an untrusted signature, which is then tweaked to change the  signature algorithm  to an invalid or unknown algorithm.  In both the latter two attack scenarios — stemming as a result o
Researchers Demonstrate 2 New Hacks to Modify Certified PDF Documents

Researchers Demonstrate 2 New Hacks to Modify Certified PDF Documents

May 29, 2021Ravie Lakshmanan
Cybersecurity researchers have disclosed two new attack techniques on certified PDF documents that could potentially enable an attacker to alter a document's visible content by displaying malicious content over the certified content without invalidating its signature. "The attack idea exploits the flexibility of PDF certification, which allows signing or adding annotations to certified documents under different permission levels,"  said  researchers from Ruhr-University Bochum, who have  systematically   analyzed  the security of the PDF specification over the years. The findings were presented at the 42nd IEEE Symposium on Security and Privacy ( IEEE S&P 2021 ) held this week. The two attacks — dubbed  Evil Annotation and Sneaky Signature attacks  — hinge on manipulating the PDF certification process by exploiting flaws in the specification that governs the implementation of digital signatures (aka approval signature) and its more flexible variant called certifica
Signature Validation Bug Let Malware Bypass Several Mac Security Products

Signature Validation Bug Let Malware Bypass Several Mac Security Products

June 12, 2018Swati Khandelwal
A years-old vulnerability has been discovered in the way several security products for Mac implement Apple's code-signing API that could make it easier for malicious programs to bypass the security check, potentially leaving millions of Apple users vulnerable to hackers. Josh Pitts, a researcher from security firm Okta, discovered that several third-party security products for Mac—including Little Snitch, F-Secure xFence, VirusTotal, Google Santa, and Facebook OSQuery—could be tricked into believing that an unsigned malicious code is signed by Apple. Code-signing mechanism is a vital weapon in the fight against malware, which helps users identify who has signed the app and also provides reasonable proof that it has not been altered. However, Pitts found that the mechanism used by most products to check digital signatures is trivial to bypass, allowing malicious files bundle with a legitimate Apple-signed code to effectively make the malware look like it has been signed by
Android Flaw Lets Hackers Inject Malware Into Apps Without Altering Signatures

Android Flaw Lets Hackers Inject Malware Into Apps Without Altering Signatures

December 09, 2017Mohit Kumar
Millions of Android devices are at serious risk of a newly disclosed critical vulnerability that allows attackers to secretly overwrite legitimate applications installed on your smartphone with their malicious versions. Dubbed Janus , the vulnerability allows attackers to modify the code of Android apps without affecting their signature verification certificates, eventually allowing them to distribute malicious update for the legitimate apps, which looks and works same as the original apps. The vulnerability ( CVE-2017-13156 ) was discovered and reported to Google by security researchers from mobile security firm GuardSquare this summer and has been patched by Google, among four dozen vulnerabilities, as part of its December Android Security Bulletin . However, the worrisome part is that majority of Android users would not receive these patches for next few month, until their device manufacturers (OEMs) release custom updates for them, apparently leaving a large number of sma
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