Malicious PDF — malware analysis report

Static analysis result for SHA-256 833bb06170357e17…

MALICIOUS

PDF

73.0 KB Created: 2021-09-06 21:49:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 15e4556f18d176e37a29e6f3c8fce570 SHA-1: 4dfc146360f7cc099a59a9c71870805e534bba7f SHA-256: 833bb06170357e173f62c10a39150887d82abdc9e2096882a1dce4754b049728
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file contains a large number of external links, many pointing to domains that appear to be compromised or disposable, suggesting a link farm or SEO spamming operation. The ML classifier strongly indicated maliciousness, and the presence of numerous URLs on potentially compromised CMS upload directories supports this. No scripts were extracted, but the overall structure and URL distribution are indicative of a malicious distribution or redirection scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 5

  • 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.
  • 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://chcial.ru/uplcv?utm_term=arihant+bitsat+book+2019+pdf+free+download PDF link annotation
    • https://cald-lighting.com/wp-content/plugins/super-forms/uploads/php/files/02180cedc7fac36fcad78d4a4df5ba6f/fugopikilofekom.pdfIn PDF document text
    • http://yilip.net/userData/board/file/zutufekawalarelalavuvuju.pdfIn PDF document text
    • https://creationstationdance.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a65b7c5848c---90147067060.pdfIn PDF document text
    • http://www.luminicaambiental.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607900d050a51---95288485859.pdfIn PDF document text
    • https://mebelihome.ru/upload_picture/42414670291.pdfIn PDF document text
    • https://oknoplus-omsk.ru/wp-content/plugins/super-forms/uploads/php/files/6b292d64007992674789d908a109e7a6/jubawuwapobanegimixofo.pdfIn PDF document text
    • https://studiovizia.com/webroot/img/content/files/gomigupesew.pdfIn PDF document text
    • https://www.formwork.co.uk/wp-content/plugins/super-forms/uploads/php/files/oecdsr9q3ot8b5p61mlan5h7ds/gabibutujetobezetetaf.pdfIn PDF document text
    • http://industrialsupplies.pk/userfiles/files/rakapugiliba.pdfIn PDF document text
    • https://asthasupermarket.com/userfiles/file/vuvuwoxusejemisikabapex.pdfIn PDF document text
    • http://hyunbulsa.org/~ewedd2/userfiles/file/93931834479.pdfIn PDF document text
    • http://www.iqubz.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f91cfd7958---91073201741.pdfIn PDF document text
    • https://personnelcle.com/userfiles/file/89429567052.pdfIn PDF document text
    • https://ehblending.com/wp-content/plugins/super-forms/uploads/php/files/0a334a1e6fe184ec507b52204dd85b77/diruvawejezobuk.pdfIn PDF document text
    • http://thaide.org/userfiles/file/4324090942.pdfIn PDF document text
    • http://www.jhannahs.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a5c70af31aa---pamakavozu.pdfIn PDF document text
    • http://salkim.com/userfiles/file/bifirewotewulofezus.pdfIn PDF document text
    • https://k-newsletter.com/ckupload/files/janomogaviretupojajuwet.pdfIn PDF document text
    • http://miamiwars.pl/wp-content/plugins/super-forms/uploads/php/files/cda3a7fcc950775efcb6704006468e3b/pimepawikerodin.pdfIn PDF document text
    • http://ne-moloko.ee/wp-content/plugins/super-forms/uploads/php/files/f44bd09f6c4d8a7d69ab64779951a1d5/62915905931.pdfIn PDF document text
    • http://amfmeg.org/wp-content/plugins/formcraft/file-upload/server/content/files/160a1a7abc5bac---16997968272.pdfIn PDF document text
    • http://www.immiflex.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609f16f4d1a72---13808643433.pdfIn PDF document text
    • 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_off0000b992.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB992 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d1a4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD1A4 16256 bytes
SHA-256: e264c035466fddc7e55c05d8b6302041c820020fa6dabfe7fb367307b13ef746
font_02_sfnt_off0000fb3e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB3E 11356 bytes
SHA-256: cc36dea749c1a5aacce2e1ff167f399f179c12de39e26f9acaa02dc15b109d83