Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b2ab92a9e8207de…

MALICIOUS

PDF

95.1 KB Created: 2021-05-24 23:02:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: c145c880182d490533856c1037bbf257 SHA-1: c8eff2a7bcfc17ad05af8ae1ec57dc12f89f8a0c SHA-256: 4b2ab92a9e8207de02069743a34212841f1185b57db66549ed0ff97ae0b43eb1
254 Risk Score

Malware Insights

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

This PDF file contains numerous links designed to lead users to external websites, a technique often used in phishing campaigns. One critical heuristic identified a link to a known malicious redirector infrastructure, specifically 'https://yafferge.ru/strik?utm_term=chinese+o+level+2019+answer+key+lc', which is presented as an answer key. The ML classifier also strongly indicated maliciousness. The presence of embedded links and the redirector URL suggest an attempt to trick users into visiting a compromised site, likely for credential harvesting or further malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • Image lure linking to an SEO redirector (free-download phishing) high PDF_SEO_UTM_REDIRECTOR_LINK
    PDF embeds an image with little or no body text and a clickable link to a multi-word utm_term / FeedBurner-proxied SEO redirector — the 'free ebook / solution-manual / document download' phishing family that ranks for natural-language search queries and routes the user into a payload/redirect chain. The PDF carries no exploit; the risk is the linked destination. Flagged structurally (image lure + SEO redirector) so it does not depend on a ClamAV/ML signature, and regardless of how many filler text pages the lure carries.
  • 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://yafferge.ru/strik?utm_term=chinese+o+level+2019+answer+key+lc In PDF document text
    • https://rozenawaxu.weebly.com/uploads/1/3/4/5/134517597/jubugexokogesat_jezuroriwasi_mamasedizukogi.pdfIn PDF document text
    • https://vabakapis.weebly.com/uploads/1/3/1/4/131453405/59e23e.pdfIn PDF document text
    • https://kibipevanisimak.weebly.com/uploads/1/3/4/7/134770361/3481c2.pdfIn PDF document text
    • https://womegirig.weebly.com/uploads/1/3/4/5/134506381/lakok_wipofemedaxid_runugizede_vonepitunox.pdfIn PDF document text
    • https://zagumukukawikam.weebly.com/uploads/1/3/4/6/134608037/9de924591aa3c70.pdfIn PDF document text
    • http://fedorahosted.org/lohitIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/mefovu/lowusibenirelurexoxorog.pdfIn PDF document text
    • https://s3.amazonaws.com/vebogotexaf/elite_dangerous_planet_mining_guide.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/dc3f5803-add5-4ac1-9c60-d1026e578b7c/craftsman_sliding_miter_saw_review.pdfIn PDF document text
    • https://s3.amazonaws.com/bokelur/83290434216.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/34dbabfb-8be8-446f-aa08-6c4d33b3348c/adding_and_subtracting_fractions_word_problems_practice.pdfIn PDF document text
    • https://s3.amazonaws.com/belopudevuzuza/axial_yeti_xl_sway_bar_kit.pdfIn PDF document text
    • https://s3.amazonaws.com/wunojipu/lidegoredibonuvanux.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/7c798271-27ee-4eda-8b46-40eea43f1d3c/jvc_everio_video_camera_battery.pdfIn PDF document text
    • https://s3.amazonaws.com/pulujolatepuv/ligutolixudiguve.pdfIn PDF document text
    • https://s3.amazonaws.com/siwixomudit/55866679178.pdfIn PDF document text
    • https://s3.amazonaws.com/lomuper/chalo_movie_ringtones_for_mobile.pdfIn PDF document text
    • https://s3.amazonaws.com/wewuxuviwar/36002514353.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/fba64d81-bbf0-4643-8b94-27d0166eef5c/how_much_to_replace_thermostat_housing.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/04acbf0a-6853-4182-a63a-0e7732fbfb8d/46494822985.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/20da07d3-96d9-4fe9-8713-36302de166c3/rozowapekaxasevujis.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/cf894339-cfe4-4d92-b8b4-6fa2668b95e9/35456431561.pdfIn PDF document text
    • https://s3.amazonaws.com/zizene/90965813276.pdfIn PDF document text
    • https://s3.amazonaws.com/taguxif/how_to_cook_costco_spiral_ham_in_crock_pot.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/bfe29d4e-52c7-44b0-8b50-72ba0a773e4a/focusrite_scarlett_18i20_2nd_gen_software.pdfIn PDF document text
    • https://s3.amazonaws.com/begijufadi/sovelamegejumezavasozela.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
    • https://savannah.gnu.org/projects/freefont/In PDF document text
    • http://www.gnu.org/licenses/In PDF document text
    • http://www.gnu.org/copyleft/gpl.htmlIn PDF document text
    • http://scripts.sil.org/OFLIn PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 6

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_005_off000127ce.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x127CE 1540 bytes
SHA-256: 496bf527228802f70ed0cc252007dd9ee4e3fc3a20ba377a1a00aecd615d5bdc
font_00_sfnt_off0000eb50.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB50 6812 bytes
SHA-256: 31d4dd97cf5147e6b059c24d0fa5ef82248f625d272ff84a9e6c0d2f8a785f9a
font_01_sfnt_off0000fc54.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC54 7192 bytes
SHA-256: 3efa284e82d6f4f2effe5d65b3f1d9a7ada17dda1ab769c142c384bf637fe0df
font_02_sfnt_off000114b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x114B9 5592 bytes
SHA-256: e43b8d0f0dcc54a37bf85024446b3083675e872c6e18e39322743e88a9ea3aae
font_04_sfnt_off00013016.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13016 11228 bytes
SHA-256: 1c64cb0322d82d253b8b1d8e2a60b435509977a09487e79970cc2432e349bc61
font_05_sfnt_off00015686.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15686 16160 bytes
SHA-256: b91ebbfc40a94f10b2fcfc4d08542e4cd4fc38dcff43bcfefe5d572695fcce17