Malicious PDF — malware analysis report

Static analysis result for SHA-256 51a8168d02b5c096…

MALICIOUS

PDF

91.6 KB Created: 2021-07-28 04:02:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-16
MD5: ff6c122548541bdc35c111e88910ac6d SHA-1: 8ad6db1fb96099e1e329a39c041635a2b80c1927 SHA-256: 51a8168d02b5c096aa990b9ec4042061bbfabceb2d1e0f4d70c1681b55e29fd5
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

This PDF file was identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The heuristics reveal it functions as a link farm, with numerous URLs pointing to compromised WordPress sites. These links likely serve to distribute further malware or host phishing content, making the primary attack pattern the distribution of malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9970

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 http://www.catalogodecineargentino.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e1827ad1055---14206704315.pdf In PDF document text
    • http://safarang.com/basefile/files/bedubu.pdfIn PDF document text
    • http://getvisa.ru/images/File/sujironegaxeroxuga.pdfIn PDF document text
    • https://maydongy.com/wp-content/plugins/super-forms/uploads/php/files/fu7orbfrtl7kblor0sf6gihr75/fezurifumusufobi.pdfIn PDF document text
    • http://learningkey.org/userfiles/53273132209.pdfIn PDF document text
    • https://rzfmuhasebe.com/userfiles/file/53387126108.pdfIn PDF document text
    • https://utilitydiscount.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b13f834b24---melajeburo.pdfIn PDF document text
    • http://cariboohose.com/userfiles/file/41912142809.pdfIn PDF document text
    • https://chulintemple.org/CKEdit/upload/files/mesikaxusawikiboveperuke.pdfIn PDF document text
    • http://innobiztour.com/FileData/ckfinder/files/20210716_186723DC398B5AE8.pdfIn PDF document text
    • https://www.vedaaz.com/wp-content/plugins/super-forms/uploads/php/files/7ba0552e4868165225a0106e64eabaf4/mufulujuruk.pdfIn PDF document text
    • https://airshow-bg.com/file/93414527123.pdfIn PDF document text
    • https://e-uchebnici.com/img/file/27708547908.pdfIn PDF document text
    • https://www.properties-thassos.com/wp-content/plugins/super-forms/uploads/php/files/ra7bbamrq7h3v1u4cghdvftuid/puriwavuvomiti.pdfIn PDF document text
    • http://www.opencalgary.org/wp-content/plugins/formcraft/file-upload/server/content/files/1607abfa52a03b---69339332234.pdfIn PDF document text
    • http://dringraldi.com/clients/7/73/73ccc230e5ee2b020474e4a43bcd07af/File/36483876889.pdfIn PDF document text
    • http://enjoybowlramenandpoke.com/uploads/files/famoberilewifaruxisewoj.pdfIn PDF document text
    • https://stopserv.ru/files/file/65487123211.pdfIn PDF document text
    • https://angkoronetour.com/userfiles/file/14570589148.pdfIn PDF document text
    • http://optimus.org.au/wp-content/plugins/formcraft/file-upload/server/content/files/160898028350b7---botakinuxodefanezusoju.pdfIn PDF document text
    • https://bonafideonline.com.ar/wp-content/plugins/super-forms/uploads/php/files/764c6c0bf964ab52f8090155569f172e/16030068804.pdfIn PDF document text
    • http://synthecinter.com/userfiles/files/22082689685.pdfIn PDF document text
    • http://redwoodpwr.com/wp-content/plugins/super-forms/uploads/php/files/ll00rg5r95uka0m659mpql8cu3/nakifaxulapati.pdfIn PDF document text
    • https://www.a2zmedical.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1608962b345624---15992798484.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=idsa+urinary+tract+infection+guidelines+2018PDF 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_off000100e4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100E4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000118f6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x118F6 17136 bytes
SHA-256: 07494f2d6a03ae38ef98fdaeda267938d30ecb7cebe530fc3987016026b5cdf7
font_02_sfnt_off000145b6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x145B6 11320 bytes
SHA-256: eaacf0d2ae65f7b2c58c631aea8e4457dcda03ea1ba4b8ea56e871e34d950564