Malicious PDF — malware analysis report

Static analysis result for SHA-256 79831a601f1bccb2…

MALICIOUS

PDF

82.0 KB Created: 2021-09-11 16:13:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 5e035a484ef8eec60d34948960675e33 SHA-1: a702a677f6c21cda40d697905224f16ab87db02e SHA-256: 79831a601f1bccb295369b2471e08eb4f92de645ee4d5ea2caf9171e641c64f9
104 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The sample is a PDF document that contains JavaScript actions and a significant number of external URIs. Several heuristics indicate that these URIs form a link farm, with some pointing to compromised CMS uploads and others on disposable hosting. The ML classifier also flagged this PDF as malicious. While no specific payload is directly executed from the PDF, the presence of JavaScript and the link farm suggest an intent to redirect users to malicious sites, potentially for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 6

  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • JavaScript action low PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://twinslock.com/locktactyuma/userfiles/file/mosizemoxevovugudero.pdf In PDF document text
    • http://synphabase.ch/upload/file/pokusepujubulixisivetun.pdfIn PDF document text
    • http://tv-sat.cz/userfiles/file/kijewogulum.pdfIn PDF document text
    • https://tskrea.com/userfiles/file/butadewoditin.pdfIn PDF document text
    • http://df-2.de/images/daten/file/laxekak.pdfIn PDF document text
    • http://centroolosprato.it/userfiles/files/24198309523.pdfIn PDF document text
    • https://bharatiyabhashaparishad.org/ckfinder/userfiles/files/bunixidoxazufotev.pdfIn PDF document text
    • http://iltorg.ru/upload/file/wogopiwo.pdfIn PDF document text
    • https://www.entornopublicitario.com/wp-content/plugins/super-forms/uploads/php/files/fc32adb552b24bf17a18a04beaa5a02f/ditomokaregedozixebedo.pdfIn PDF document text
    • http://ahnil.com/userData/board/file/51882956025.pdfIn PDF document text
    • http://saydersan.com/firma/files/74678659802.pdfIn PDF document text
    • http://pass38.com/images/contentimages/files/16832652994.pdfIn PDF document text
    • http://aligokdemir.com/resimler/files/43806879711.pdfIn PDF document text
    • http://jrmhandling.nl/upload/file/tivoxopijefapas.pdfIn PDF document text
    • https://goooinggroup.com/userfiles/files/20210903_023422.pdfIn PDF document text
    • http://vivaibonomo.it/userfiles/files/latezofosiwupami.pdfIn PDF document text
    • http://123flower.doweb.kr/upload/files/dapusaxirovu.pdfIn PDF document text
    • http://tlumacz-bialystok.pl/pliki/file/jiretupibol.pdfIn PDF document text
    • http://www.hypnotiseur.com/wp-content/plugins/formcraft/file-upload/server/content/files/161383fef608f7---gobuvefusode.pdfIn PDF document text
    • http://www.grundys.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16132f9c94d959---80331814262.pdfIn PDF document text
    • https://www.corpeverest.com/ckfinder/userfiles/files/finopurodasib.pdfIn PDF document text
    • http://the-bom.kr/upfile/files/28127154605.pdfIn PDF document text
    • http://fundacjaproartis.pl/javascript/ckfinder/userfiles/files/61654605396.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/FevRqgeaUVY/uplcv?utm_term=punjab+educare+app+download+apkPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d8d2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD8D2 18724 bytes
SHA-256: cde4924b0b1d8d240bc9201380d0e88609e38f4a952dee1569e34c1d7d0da487
font_01_sfnt_off0001098f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1098F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000121a6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x121A6 10696 bytes
SHA-256: 4dde5c3f1e56ad1cb2b8ba7d12d3e441b6bb970ec1491294d9a8fb68e3671484