Malicious PDF — malware analysis report

Static analysis result for SHA-256 fdd99819e68cebcc…

MALICIOUS

PDF

71.4 KB Created: 2021-09-24 19:01:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: d616ec7041366d4e7562a7680a234b32 SHA-1: 184008b7e49984d6b289768e58a6849c6bfdef2d SHA-256: fdd99819e68cebcc7af640f8f341679f6041b2424c061ee11e4d809ebef52d5d
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF was flagged by multiple heuristics as malicious, including a ML classifier and ClamAV, indicating it is likely a phishing or malware distribution lure. The presence of numerous external URIs, many pointing to disposable hosting and using UTM parameters, suggests a link farm designed to redirect users to malicious content. No scripts were extracted, but the PDF structure itself is indicative of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://laborke.ru/uplcv?utm_term=p30+android+11 PDF link annotation
    • http://korytnica.net/data/files/24463835259.pdfIn PDF document text
    • http://captaincook.hu/userfiles/file/keririxazuw.pdfIn PDF document text
    • https://pracowniatechart.pl/fckpliki/file/32011158873.pdfIn PDF document text
    • https://cungcapthitdetuoi.com/app/webroot/files/images/pages/files/rovegad.pdfIn PDF document text
    • http://train-in-japan.com/images/blog/file/puzagekutaro.pdfIn PDF document text
    • http://snft.ro/media/file/fixotizenobili.pdfIn PDF document text
    • https://regalcabs.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1614ca2591c5ac---tajeriwijefuvufem.pdfIn PDF document text
    • http://valsadindustries.com/userfiles/file/tipagusufisixozutolurami.pdfIn PDF document text
    • https://samsungklima.net/upload/ckfinder/files/41797609935.pdfIn PDF document text
    • http://j1medical.com/uploaded/file/wogojatonaduzavuxeg.pdfIn PDF document text
    • https://mayphotocopydogia.com/upload/files/zevirosare.pdfIn PDF document text
    • http://85560891.com/upfolder/e/files/20210903205323.pdfIn PDF document text
    • http://onroerendgoedindex.nl/images/uploads/kalegumiforubisagilot.pdfIn PDF document text
    • http://www.yeosung21.or.kr/ckfinder/userfiles/files/1630465214.pdfIn PDF document text
    • https://chorland-dining.com/webroot/editor-uploads/files/93276579903.pdfIn PDF document text
    • http://cukorbetegshop.hu/files/86567035900.pdfIn PDF document text
    • http://bigcool.net/webroot/img/files/51101709845.pdfIn PDF document text
    • http://xn--54-dlcdkamdj4btild5b.xn--p1ai/ckfinder/userfiles/files/56419353166.pdfIn PDF document text
    • https://nailseasupportgroup.com/wp-content/plugins/super-forms/uploads/php/files/0b8d4f520da08f100b82d0333a5979e3/67463209794.pdfIn PDF document text
    • https://spbmworld.com/anaeter_capital/siteadmin/userfiles/files/4036484336.pdfIn PDF document text
    • http://newbiesites.com/userfiles/file/19724290236.pdfIn PDF document text
    • http://youngshiny.com/userfiles/file/1631335715.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_off0000b1fc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB1FC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ca13.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA13 10144 bytes
SHA-256: 42d336e793d2d42146508ac944e0ac5a842284ea5a8c7218d55fe679fa346c2a
font_02_sfnt_off0000e0c8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0C8 18328 bytes
SHA-256: b40de294fc9685f527540f1505f758ab2f75cced7c5629277e21c44043a18217