Malicious PDF — malware analysis report

Static analysis result for SHA-256 e04e21f04136b9f8…

MALICIOUS

PDF

74.3 KB Created: 2021-10-06 15:46:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: 4a12e1b51f5c408ad9a57db457d08ebd SHA-1: 8316d9d70c2321af2117e2117711c47a7bb6eacf SHA-256: e04e21f04136b9f83bd085a3a35ba7901c5ff5d9c0c2d8af8f96280ca7f37781
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ClamAV and an ML classifier, and exhibits characteristics of a link farm on disposable hosting. Multiple PDF links point to external URLs, with one specifically identified as an algorithmically-generated URL likely leading to a malicious payload. The document body is heavily obfuscated, preventing analysis of its direct content, but the presence of numerous external links strongly suggests a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://catamma.ru/uplcv?utm_term=input+and+out+devices+of+computer+pdf PDF link annotation
    • https://artgallery.devctn.com/ckfinder/userfiles/files/sadelesedajovugubimo.pdfIn PDF document text
    • http://jungam21.com/upfiles/file/1631933643.pdfIn PDF document text
    • http://aven.su/userfiles/file/fizejozobuxafoxizabilaz.pdfIn PDF document text
    • http://wsystem.sk/userfiles/files/12601057568.pdfIn PDF document text
    • https://wintechindia.in/ckfinder/userfiles/files/lemebiniredosezogaxi.pdfIn PDF document text
    • http://podarox.ru/public/files/givevixebudokij.pdfIn PDF document text
    • http://phukiendoxe.com/media/ftp/file/fogapowurubudimepos.pdfIn PDF document text
    • http://sakirnoopo.ru/wp-content/plugins/super-forms/uploads/php/files/4e6d5e227be878b8e266ae7ae414dfb0/zakutubo.pdfIn PDF document text
    • http://clinicaveterinariacittadivignola.com/userfiles/files/wezaninidagetamakuruzu.pdfIn PDF document text
    • https://www.studioline.ie/ckfinder/userfiles/files/zekojitopupifawinavuxa.pdfIn PDF document text
    • https://dascalita.ro/app/webroot/files/userfiles/files/14103465476.pdfIn PDF document text
    • http://dzstock.com/Upfiles/file/93962373036.pdfIn PDF document text
    • https://pustelnik-budownictwo.pl/ckfinder/userfiles/files/vepuzifezuped.pdfIn PDF document text
    • https://pisangmanis.com/contents/files/59608083626.pdfIn PDF document text
    • http://3wsystems.com/shipinc/userfiles/files/6265563466.pdfIn PDF document text
    • http://sun-green.de/ckfinder/userfiles/files/kexedolijopa.pdfIn PDF document text
    • http://stromzeleny.cz/file/8066817628.pdfIn PDF document text
    • http://hanlacsclub.com/ckupload/files/zijidefisuxoz.pdfIn PDF document text
    • https://www.hkfew.org.hk/ckfinder/userfiles/files/88243044614.pdfIn PDF document text
    • http://xn--h1aeekk.xn--p1ai/files/file/wososunimeka.pdfIn PDF document text
    • https://limsurempat.com/contents/files/28228441588.pdfIn PDF document text
    • http://dienlanhhuubinh.com/upload/files/dufugapodawukav.pdfIn PDF document text
    • http://myphamso1.net/uploads/files/56731436646.pdfIn PDF document text
    • https://siemreaptraveltours.com/userfiles/file/11831256560.pdfIn PDF document text
    • http://serting.eu/userfiles/files/46273533584.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_off0000c07e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC07E 16092 bytes
SHA-256: 29332e380e0ecd894fc2a18db0cd105734e7bc6015477eded2005603e9569c27
font_01_sfnt_off0000e9e0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE9E0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000101f7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x101F7 10852 bytes
SHA-256: a50aeb1ee11e449537c2c6c4b22851e082e3247c0648f637674d7f798ea8317b