Malicious PDF — malware analysis report

Static analysis result for SHA-256 a7e11fc07a94838d…

MALICIOUS

PDF

43.4 KB Created: 2020-08-31 18:50:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 14a90c45137acbc70ad0b95f23ce3722 SHA-1: 485505b571def8074e6634f05c1ebee2386c048b SHA-256: a7e11fc07a94838db0bd011f6814bfb9cb86d7b4ca66bacdcc1b2c26d7ef9edc
152 Risk Score

Malware Insights

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

The PDF file contains a large number of embedded links, many of which point to external PDF files hosted on static.usrfiles.com, forming a link farm. One of these links, https://ttraff.ru/wix?keyword=elf+on+the+shelf+goodbye+letter+template, is identified as a known malicious redirector. The ML classifier also strongly flagged this PDF as malicious. The document body contains garbled text but includes the same malicious URL.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • 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.
  • 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://ttraff.ru/wix?keyword=elf+on+the+shelf+goodbye+letter+template
    • https://static.usrfiles.com/ugd/c5d40f_31f02883ed3a45abb7c503f71977f0a8.pdf
    • https://static.usrfiles.com/ugd/de02f3_4542aadcb8b5478d80383718fd7ebb4c.pdf
    • https://static.usrfiles.com/ugd/e4a001_d0c334f79c084cb1aef3146dede4646e.pdf
    • https://static.usrfiles.com/ugd/b7ab08_ebffb786bc1f44849caa5397f77b1329.pdf
    • https://static.usrfiles.com/ugd/9ea91e_a8686f72cf3e4bef9c48e826fd4471f3.pdf
    • https://cdn.shopify.com/s/files/1/0431/2901/2381/files/wawewopazumewavepabig.pdf
    • https://cdn.shopify.com/s/files/1/0436/0300/1502/files/converting_metric_units_worksheet_grade_4.pdf
    • https://static.usrfiles.com/ugd/0b46e6_983f5409cbf94fad8dc43fdea4b3b4b9.pdf
    • https://static.usrfiles.com/ugd/b8c837_4435acaf8f07454098913d9b1539bec5.pdf
    • https://static.usrfiles.com/ugd/e745be_6dc9814305624a7e93d685d28cf958ea.pdf
    • https://static.usrfiles.com/ugd/269bb8_9ee08641534c481c98f4bd9eed5a4114.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00005dd9.bin
88b275a329b1fa77c0bc57f01fc19d1c3291ff58ef8ca01f81d7f586b94ff8e2
pdf-font-stream PDF embedded font (sfnt) at offset 0x5DD9 5392 bytes
font_01_sfnt_off00007002.bin
642f48d7df5a1c14d4c4c0c63c49cbc3427b544d4bf9c59636bd2ae7127ff004
pdf-font-stream PDF embedded font (sfnt) at offset 0x7002 10092 bytes
font_02_sfnt_off00009289.bin
b50a2106bf82917db0cd3cf88f63c5e8cc3298b343ace5cffc591b35df33d24c
pdf-font-stream PDF embedded font (sfnt) at offset 0x9289 4324 bytes